The Project Gutenberg EBook of Butterflies Worth Knowing, by Clarence M. Weed
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Title: Butterflies Worth Knowing
Author: Clarence M. Weed
Release Date: August 8, 2011 [EBook #37009]
Language: English
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[Illustration: _From a drawing by S. Shimotori_ _See page 120_
THE REGAL FRITILLARY, FEMALE]
_LITTLE NATURE LIBRARY_
=======================
BUTTERFLIES
WORTH KNOWING
BY CLARENCE M. WEED, D. Sc.
AUTHOR OF
_Seeing Nature First_, _Nature Biographies_, _Ten New
England Blossoms_, _The Flower Beautiful_, _etc._
[Illustration: "Fructus Quam Folia"]
_Illustrated by Forty-eight Plates
Thirty-two in Color_
PUBLISHED BY
DOUBLEDAY, PAGE & COMPANY
FOR
NELSON DOUBLEDAY, INC.
1922
_Copyright, 1917, by_
DOUBLEDAY, PAGE & COMPANY
_All rights reserved, including that of
translation into foreign languages,
including the Scandinavian_
PRINTED IN THE UNITED STATES
AT
THE COUNTRY LIFE PRESS, GARDEN CITY, N. Y.
PREFACE
In this little book an attempt has been made to discuss the more
abundant and widely distributed butterflies of eastern North America
from the point of view of their life histories and their relations to
their surroundings. In so doing I have of course availed myself of the
written records of a host of students of butterflies, without whose
labors no such volume would be possible. Among these two names stand
out preëminent--William H. Edwards and Samuel H. Scudder. Each was the
author of a sumptuous work on American butterflies to which all later
students must refer, both for information and for inspiration. Many
others, however, have made notable contributions to our literature of
these ethereal creatures. Every seeker after a knowledge of
butterflies will soon find himself indebted to the writings of such
investigators as the Comstocks, Denton, Dickerson, Dyar, Fernald,
Fiske, Fletcher, French, Hancock, Holland, Howard, Longstaff, Newcomb,
Riley, Skinner, Wright, and many others. I am glad to express my
obligations to all of these for the assistance their records have
given in the preparation of this book.
While a vast amount of knowledge of butterflies has already been
discovered there is still more to be learned concerning them, and
throughout these pages I have attempted to indicate the more important
opportunities awaiting investigation. The day of the field naturalist
has come again and the butterflies are well worthy of careful
observations by many interested students.
The illustrations in the book require a word of credit. The eleven
color plates of adult butterflies with wings spread have been made
direct from a set of the remarkable transfers which Mr. Sherman F.
Denton has been preparing for the last quarter-century, this
particular set having been prepared especially for this book.
Transfers of this sort were used as insets in Mr. Denton's work on the
"Moths and Butterflies of the United States," published in a limited
edition by J. B. Millet Company, Boston. The other plates not
reproduced from photographs are from drawings by Miss Mary E. Walker
or Mr. W. I. Beecroft. In case the photographs are not of my own
taking, credit is given beneath each. Two of my photographs have
already appeared in "Seeing Nature First" and are here used by
permission of its publishers, J. B. Lippincott Company.
C. M. W.
STATE NORMAL SCHOOL,
Lowell, Mass.
CONTENTS
PAGE
PREFACE v
LIST OF COLORED ILLUSTRATIONS xi
LIST OF OTHER ILLUSTRATIONS xiii
PART I
INTRODUCTION
BUTTERFLY TRANSFORMATIONS 5
BUTTERFLIES AND MOTHS 13
THE SCENTS OF BUTTERFLIES 15
BUTTERFLY MIGRATIONS 16
HIBERNATION OR WINTER LETHARGY 17
AESTIVATION OR SUMMER LETHARGY 21
FEIGNING DEATH IN BUTTERFLIES 22
COLORATION OF BUTTERFLIES 24
SELECTIVE COLOR SENSE IN BUTTERFLIES 32
WARNING COLORATION AND MIMICRY 33
HELIOTROPISM IN BUTTERFLIES 35
PARASITIC ENEMIES OF BUTTERFLIES 40
REARING BUTTERFLIES FROM CATERPILLARS 43
PHOTOGRAPHING BUTTERFLIES 47
BUTTERFLY COLLECTIONS 49
PART II
THE TRUE BUTTERFLIES--SUPERFAMILY _Papilionoidea_ 55
PARNASSIANS (_Parnassiinae_) 56
SWALLOWTAILS (_Papilionidae_) 57
Black Swallowtail; Giant Swallowtail; Blue Swallowtail;
Green-clouded Swallowtail; Tiger Swallowtail; Palamedes
Swallowtail; Short-tailed Papilio; Zebra Swallowtail;
Synopsis of the Swallowtails
WHITES, ORANGE-TIPS, AND YELLOWS (_Pieridae_) 82
The Tribe of the Whites: White or Imported Cabbage Butterfly;
Gray-veined White; Checkered White; Great Southern White;
Synopsis of the Whites 83
The Tribe of the Orange-tips: Falcate Orange-tip;
Olympian Orange-tip; Synopsis of the Orange-tips 92
The Tribe of the Yellows: Brimstone or Cloudless
Sulphur; Dog's-head; Clouded Sulphur; Orange
Sulphur; Pink-edged Sulphur; Black-bordered Yellow;
Little Sulphur; Dainty Sulphur; Synopsis
of the Yellows 97
NYMPHS (_Nymphalidae_) 111
The Tribe of the Fritillaries: Gulf Fritillary;
Variegated Fritillary; Diana Fritillary; Regal Fritillary;
Great Spangled Fritillary; Silver-spot Fritillary;
Mountain Silver-spot; White Mountain Fritillary;
Meadow Fritillary; Silver-bordered Fritillary;
Synopsis of the Fritillaries 115
The Tribe of the Crescent-spots: Baltimore Checker-spot;
Harris's Checker-spot; Silver Crescent; Pearl Crescent;
Synopsis of the Crescent-spots 135
The Tribe of the Angle-wings: Violet-tip; Hop-merchant
or Comma; Gray Comma; Green Comma; Red Admiral or Nettle
Butterfly; Painted Beauty; Painted Lady or Cosmopolite;
Mourning-cloak; American tortoise-shell; White J Butterfly
or Compton Tortoise; Buckeye; Synopsis of the Angle-wings
(I. Polygonias--II. Vanessids) 150
The Tribe of the Sovereigns: Viceroy; Banded Purple;
Red-spotted Purple; Vicereine; Synopsis of the Sovereigns 192
The Tribe of the Emperors: Goatweed Emperor; Gray Emperor;
Tawny Emperor; Synopsis of the Emperors 207
MEADOWS-BROWNS OR SATYRS (_Agapetidae_) 214
Common Wood Nymph or Grayling; Southern Wood Nymph;
Pearly Eye; Eyed Brown; White Mountain Butterfly; Arctic
Satyr; Little Wood Satyr; Other Meadow-browns; Synopsis of
Meadow-browns
HELICONIANS (_Heliconidae_) 229
Zebra Butterfly
MILKWEED BUTTERFLIES (_Lymnadidae_) 232
Monarch; Queen
SNOUT BUTTERFLIES OR LONG-BEAKS (_Libytheidae_) 236
Snout Butterfly
METAL-MARKS (_Riodinidae_) 239
Small Metal-mark; Large Metal-mark
GOSSAMER-WINGS (_Lycaenidae_) 240
The Tribe of the Hair-streaks: Great Purple Hair-streak;
Gray Hair-streak; Banded Hair-streak; Striped Hair-streak;
Acadian Hair-streak; Olive Hair-streak; Synopsis of the
Hair-streaks 242
The Tribe of the Coppers: Wanderer; American Copper;
Synopsis of the Coppers 252
The Tribe of the Blues: Spring Azure; Scudder's Blue;
Tailed Blue; Silvery Blue: Synopsis of the Blues 258
PART III
THE SKIPPER BUTTERFLIES--SUPERFAMILY _Hesperioidea_ 266
GIANT SKIPPERS (_Megathymidae_) 267
Yucca-borer Skipper
COMMON SKIPPERS (_Hesperiidae_) 268
The Tribe of the Larger Skippers: Silver-spotted Skipper;
Long-tailed Skipper; Juvenal's Dusky-wing; Sleepy
Dusky-wing; Persius's Dusky-wing; Sooty Wing 269
The Tribe of the Smaller Skippers: Tawny-edged Skipper;
Roadside Skipper; Least Skipper 278
LIST OF COLORED ILLUSTRATIONS
PAGE
VICEROY BUTTERFLIES VISITING STRAWBERRIES (_On Cover_)
THE REGAL FRITILLARY _Frontispiece_
THE CAROLINA LOCUST 33
THE BLACK SWALLOWTAIL 48
THE CYNTHIA MOTH 49
GIANT SWALLOWTAILS 64
THE BLUE SWALLOWTAIL 65
TWO OF THE SWALLOWTAILS: PALAMEDES AND GIANT 66
THE GREEN-CLOUDED SWALLOWTAIL 67
CATERPILLARS OF THE GREEN-CLOUDED SWALLOWTAIL 80
THE TIGER SWALLOWTAIL 96
IMPORTED CABBAGE BUTTERFLY 97
CLOUDED SULPHUR BUTTERFLY 112
THE ZEBRA SWALLOWTAIL: SUMMER FORM 112-113
THE ZEBRA SWALLOWTAIL VISITING PAPAW BLOSSOMS 112-113
SOME OF THE TRIBE OF YELLOWS 113
SILVER-SPOT FRITILLARY AND GULF FRITILLARY 128
GULF FRITILLARY, SILVER-BORDERED FRITILLARY,
AND BALTIMORE CHECKER-SPOT 129
THE HOP MERCHANT 144
THREE ANGLE-WINGS (AMERICAN TORTOISE-SHELL,
RED ADMIRAL, VIOLET-TIP): UPPER SURFACE 160-161
THREE ANGLE-WINGS (AMERICAN TORTOISE-SHELL,
RED ADMIRAL, VIOLET-TIP): LOWER SURFACE 160-161
THE PAINTED BEAUTY 161
THREE MORE ANGLE-WINGS: BUCKEYE, PAINTED BEAUTY, COSMOPOLITE 176
THE MOURNING-CLOAK 177
SOME COMMON SKIPPERS 192
THE STAGES OF THE VICEROY 193
BANDED PURPLE, RED-SPOTTED PURPLE, AND BLUE-EYED GRAYLING 208
THREE EMPEROR BUTTERFLIES 209
THE ZEBRA BUTTERFLY 224
MONARCH BUTTERFLY, CRYSALIS AND CATERPILLAR 241
SPRING AZURE, FALCATE ORANGE-TIP, BRONZE COPPER,
AND GREAT PURPLE HAIR-STREAK 256
SILVER-SPOTTED SKIPPER 273
LIST OF OTHER PLATES
PAGE
SWALLOWTAIL BUTTERFLY JUST OUT OF CHRYSALIS 16
TIGER SWALLOWTAIL; HAMMOCK CATERPILLAR 17
BUTTERFLY FEIGNING DEATH; BUTTERFLY IN HIBERNATING POSITION 32
MONARCH BUTTERFLY: CHANGE FROM CATERPILLAR TO CHRYSALIS 32-33
MONARCH BUTTERFLY: CHANGE FROM CHRYSALIS TO ADULT 32-33
MIGRATION OF MONARCH BUTTERFLIES 48-49
THE IMPROVED OPEN VIVARIUM 48-49
BLACK SWALLOWTAIL VISITING THISTLE 64-65
IMPORTED CABBAGE BUTTERFLY, MAGNIFIED 64-65
IMPORTED CABBAGE BUTTERFLY; BLUE-EYED GRAYLING 81
FOUR-FOOTED BUTTERFLIES: VICEROY AND MOURNING-CLOAK 145
MONARCH BUTTERFLY RESTING; FLASHLIGHT PHOTOGRAPH
OF MONARCHS IN MIGRATION 160
PHOTOGRAPHS OF A PET MONARCH BUTTERFLY 225
THE SNOUT BUTTERFLY; THE GIANT SWALLOWTAIL 240
STAGES OF THE GRAY HAIR-STREAK 257
THE SILVER-SPOTTED SKIPPER 272
BUTTERFLIES WORTH KNOWING
BUTTERFLIES
PART I
INTRODUCTION
In popular esteem the butterflies among the insects are what the birds
are among the higher animals--the most attractive and beautiful
members of the great group to which they belong. They are primarily
day fliers and are remarkable for the delicacy and beauty of their
membranous wings, covered with myriads of tiny scales that overlap one
another like the shingles on a house and show an infinite variety of
hue through the coloring of the scales and their arrangement upon the
translucent membrane running between the wing veins. It is this
characteristic structure of the wings that gives to the great order of
butterflies and moths its name Lepidoptera, meaning scale-winged.
In the general structure of the body, the butterflies resemble other
insects. There are three chief divisions: head, thorax, and abdomen.
The head bears the principal sense organs; the thorax, the organs of
locomotion; and the abdomen, the organs of reproduction.
By examining a butterfly's head through a lens it is easy to see the
principal appendages which it bears. Projecting forward from the
middle of the top is a pair of long feelers or antennae. Each of these
consists of short joints which in general may be divided into three
groups: first, a few large joints at the base connecting the feeler
with the head; second, many rather small joints which make up the
principal length; third, several larger joints which make up the outer
part or "club" of the antennæ. In the case of the Skippers, there are
in addition a number of small joints coming to a sharp point at the
end of the club. Just below the insertion of the antennae on each side
of the head are the large compound eyes, which are almost
hemispherical. With a powerful glass, one can see the honeycomb-like
facets, of which there are thousands, making up each eye. Just below
the eyes there are two hairy projections, called the palpi, between
which is the coiled tongue or sucking tube. (_See plate, page 64-65._)
[Illustration: Butterfly Antennae, magnified. (From Holland)]
Anatomically the thorax is divided into three parts--the prothorax,
the mesathorax, and the metathorax; but the lines of division between
these parts are not easily seen without denuding the skin of its hairy
covering. The prothorax bears the first pair of legs. The mesathorax
bears the front pair of wings and the second pair of legs. The
metathorax bears the hind pair of wings and the third pair of legs. In
many butterflies, the first pair of legs are so reduced in size that
they are not used in walking.
The abdomen is composed of eight or nine distinct rings or segments,
most of which have two spiracles or breathing pores, one on each side.
It also bears upon the end of the body the ovipositor of the female
or the clasping organs of the male.
BUTTERFLY TRANSFORMATIONS
The butterflies furnish the best known examples of insect
transformations. The change from the egg to the caterpillar or larva,
from the caterpillar to the pupa or chrysalis, and from the chrysalis
to the butterfly or imago is doubtless the most generally known fact
concerning the life histories of insects. It is a typical example of
what are called complete transformations as distinguished from the
manner of growth of grasshoppers, crickets, and many other insects in
which the young that hatches from the egg bears a general resemblance
to the adult and in which there is no quiet chrysalis stage when the
little creature is unable to eat or to move about.
[Illustration: Egg of Baltimore Butterfly, much magnified.
(From Holland)]
_The Growth of the Caterpillars_
Caterpillars are like snakes in at least one respect: in order to
provide for their increase in size they shed their skins. When a
caterpillar hatches from the egg it is a tiny creature with a soft
skin over most of its body but with rather a firm covering for its
head. While we might fancy that there could be a considerable increase
in size provided for by the stretching of the soft skin it is easy to
see that the hard covering of the head will not admit of this. So the
story of the growth of a caterpillar may be told in this way:
A butterfly lays an egg upon a leaf. Some days later the egg hatches
into a larva, which is the technical name for the second stage of an
insect's life. In the case of the butterfly we call this larva a
caterpillar. The little caterpillar is likely to take its first meal
by eating the empty egg shell. This is a curious habit, and a really
satisfactory explanation of it seems not to have been made. Its next
meal is likely to be taken from the green tissues of the leaf,
commonly the green outer surface only being eaten at this time. The
future meals are also taken from the leaf, more and more being eaten
as the larva gets older.
After a few days of this feeding upon the leaf tissues the little
caterpillar becomes so crowded within the skin with which it was born
that it is necessary to have a larger one. So a new skin begins to
form beneath the first one. Consequently the latter splits open in a
straight line part way down the middle of the back just behind the
head. Then the new head covering is withdrawn from the old one and the
caterpillar wriggles its way out of the split skin and finds itself
clothed in a new one. At first all of the tissues of the new skin are
soft and pliable and they easily take on a larger size as the body of
the caterpillar expands. A little later these tissues become hardened
and no further expansion is possible.
This process of skin-shedding is called moulting. The cast skin is
often called the exuviae. The period of the caterpillar's life between
the hatching from the egg and this moult is often called a stage or
instar--that is, the caterpillar up to the time of this moult is
living in the first caterpillar stage or instar.
During the actual moulting the caterpillar is quite active in freeing
itself from the exuviae. But as soon as it is free it is likely to
rest quietly for some hours while the tissues of the new skin are
hardening. Then it begins feeding upon the leaf again and continues
taking its meals at more or less regular intervals for several days.
By that time it will again have reached its limit of growth within
this second skin and the process of moulting must be repeated. It
takes place in the same way as before and the caterpillar enters upon
the third instar of its larval life.
This process of feeding and moulting is continued for several weeks,
the number of moults being usually four. During the later stages the
increase in size is more marked each time the skin is shed, until the
caterpillar finally reaches its full growth as a larva and is ready
for the wonderful change to the quiet chrysalis in which all its
caterpillar organs are to be transformed into the very different
organs of the butterfly.
In the case of butterfly larvae one of the most interesting features
of the growth of the caterpillar is that of the remarkable changes in
colors and patterns of marking which the caterpillar undergoes. One
who had not followed these changes would often be at a loss to
recognize caterpillars of slightly differing sizes as belonging to the
same species. These changes commonly show a remarkable adaptation to
the conditions of life, and generally tend to the concealment of the
caterpillar upon its food plant. The stages of growth of the
green-clouded swallowtail caterpillar are illustrated on plate
opposite page 80.
Before each moult the caterpillar is likely to spin a silken web upon
the leaf surface. It then entangles its claws in the web to hold
itself in place while the skin is cast. (_See plate, page 17._)
_The Change to the Chrysalis_
(_See plate, pages 32-33._)
A week or ten days after the last moult of its caterpillar growth the
larva commonly becomes full fed and ready to change to the chrysalis
state. The details of the way in which this is accomplished vary
greatly with different butterflies, as will be noted in the stories of
many species later in this book. In general, however, the caterpillar
provides a web of silk which it spins against some surface where the
chrysalis will be secure and in this web it entangles its hind legs.
Sometimes there is the additional protection of a loop of silk over
the front end of the body. After the legs have become entangled the
caterpillar hangs downward until the skin splits open along the median
line of the back and gradually shrinks upward until it is almost free,
showing as it comes off a curious creature which has some of the
characteristic features of a chrysalis. It is seldom at this stage of
the same shape as the chrysalis. When the caterpillar's skin is nearly
off this chrysalis-like object usually wriggles its body quickly in a
manner to entangle a curious set of hooks attached to the upper end in
the web of silken thread. This hook-like projection is called the
cremaster, and it serves a very important purpose in holding the
chrysalis in position.
[Illustration: Swallowtail Chrysalis, showing (_b_) the loop of
silk over thorax. (After Riley)]
As soon as the cremaster is entangled in the web the cast skin usually
falls off and for a very short period the creature hanging seems to be
neither caterpillar nor chrysalis. It is in fact in a transition stage
between the two, and it very soon shortens up and takes on the
definite form of the chrysalis, the outer tissues hardening into the
characteristic chrysalis skin.
From the fact that this chrysalis skin shows many of the
characteristic features of the future butterfly it is evident that the
change from the caterpillar to the butterfly really began during the
life of the larva. The nature of the process by which this change
takes place has long been a puzzle to scientists. For the making of a
butterfly is one of the most wonderful phenomena in the outer world,
and it has challenged the attention of many acute observers. Some two
centuries ago the great Dutch naturalist, Swammerdam, studied very
carefully the development of many insects, especially the butterfly.
He found that if he placed in boiling water a caterpillar that was
ready to pupate or become a chrysalis, the outer skin could easily be
removed, revealing beneath the immature butterfly with well-developed
legs and antennae. From these observations he was led to believe that
the process of growth was simply a process of unfolding; that is, as
Professor Packard has expressed it, "That the form of the larva, pupa,
and imago preëxisted in the egg and even in the ovary; and that the
insects in these stages were distinct animals, contained one inside
the other, like a nest of boxes or a series of envelopes one within
the other." This was called the incasement theory and it was held to
be correct by naturalists for nearly a century. It was discredited,
however, about a hundred years ago, but not until another fifty years
had passed was it definitely replaced by another and much more
convincing theory propounded by Weismann.
According to Weismann's theory, which is now well-established, the
process of development internally is a much more continuous one than
the external changes would indicate. So far as the latter are
concerned we simply say that a caterpillar changes to a chrysalis and
a chrysalis to a butterfly, the transition in each case requiring but
a very short time. Internally, however, it has been going on almost
continuously from the early life of the caterpillar. The various
organs of the butterfly arise from certain germinal disks or
"imaginal" buds, the word "imaginal" in this case being an adjective
form of imago, so that the imaginal buds are really simply buds for
the starting of growth of the various organs of the imago or adult. As
the caterpillars approach the chrysalis period these imaginal buds
rapidly develop into the various organs of the butterfly. This process
is helped along by the breaking down of many of the tissues of the
larva, this broken-down tissue being then utilized for the production
of the new organs. About the time the chrysalis is formed this
breaking-down process becomes very general, so that the newly formed
chrysalis seems largely a mass of creamy material which is soon used
to build up the various parts of the butterfly through the growth of
the imaginal buds.
_The Change to the Butterfly_
(_See plate, pages 32-33._)
There is probably no phenomenon in the world of living creatures which
has attracted more attention than the change of the chrysalis into the
butterfly. It is not strange that this is so. We see upon a tree or
shrub or wall an inert, apparently lifeless object, having no
definite form with which we can compare it with other things, having
neither eyes nor ears nor wings nor legs--an object apparently of as
little interest as a lifeless piece of rock. A few minutes later we
behold it again and note with astonishment that this apparently
inanimate being has been suddenly transformed into the most ethereal
of the creatures of earth, with an exquisite beauty that cannot fail
to attract admiration, with wings of most delicate structure for
flying through the air, with eyes of a thousand facets, with organs of
smell that baffle the ingenuity of man to explain, with vibrant
antennae, and a slender tongue adapted to feeding upon the nectar of
flowers--the most ambrosial of natural food. So it is not strange that
this emergence of a butterfly has long been the theme both of poets
and theologians and that it attracts the admiring attention of
childhood, youth, and age.
Fortunately, this change from chrysalis to butterfly may readily be
observed by any one who will take a little trouble to rear the
caterpillars or to watch chrysalids found outdoors. The precise method
of eclosion, as we call this new kind of "hatching," varies somewhat
with different species but in general the process is similar in all.
Those chrysalids which have a light colored outer skin are especially
desirable if we would watch this process. One can see through the
semi-transparent membrane the developing butterfly within, until
finally, just before it is ready to break out, the markings of the
wings and body show distinctly. If at this time the chrysalis is
placed in the sunshine it is likely to come out at once, so that you
can observe it readily. It usually breaks apart over the head and the
newly released legs quickly grasp hold of the empty skin as well as of
the support to which it is attached. It then hangs downward with a
very large abdomen and with the wings more or less crumpled up, but
decidedly larger than when they were confined within the chrysalis.
The wings, however, soon begin to lengthen as they are stretched out,
probably through the filling of the space by the body juices.
Commonly, the hind pair of wings become full size before the front
ones. In a short time the wings attain their full size, the abdomen
becomes smaller, through the discharge of a liquid called meconium,
and the butterfly is likely to walk a few steps to a better position
where it will rest quietly for an hour or two while body and wing
tissues harden. After this it is likely to fly away to lead the free
life of a butterfly. (_See plate, page 16._)
These changes from larva to chrysalis and from chrysalis to adult in
the case of the Monarch Butterfly are illustrated on the plates
opposite pages 32-33. A little study of these photographs from life
will help greatly to an understanding of the process.
Some very interesting observations have been made by Mr. J. Alston
Moffat upon the method of the expansion of the wings. In summarizing
his investigations he writes:
"When a wing is fully expanded, and for an hour or two after, the
membranes can be easily separated. Entrance for a pin-point between
them is to be found at the base of the wing where the subcostal and
median nervures come close together. The membranes are united at the
costal and inner edges, which have to be cut to get them apart; but
they are free at the outer angle. At that time the nervures are in two
parts, half in one membrane and half in the other, and open in the
centre. The fluid which has been stored up in the pupa enters the
winglet at the opening referred to, expanding the membranes as it
passes along between them, and the nervures at the same time, and when
it has extended to every portion of the wing, then it is fully
expanded. The expanding fluid is of a gummy consistency, and as it
dries, cements the membranes together, also the edges of the
half-nervures, and produces the hollow tubes with which we are so
familiar."
BUTTERFLIES AND MOTHS
The butterflies and moths both belong to the great order of
scale-winged insects--the Lepidoptera. They are distinguished,
however, by certain general characteristics, which hold true for the
most part in both groups. The butterflies fly by day; the moths fly by
night. All of the higher butterflies go into the chrysalis state
without making a silken cocoon, while most of the higher moths make
such a cocoon. The bodies of the butterflies are usually slender,
while those of the larger moths are stout. The antennae of the
butterflies are generally slender and commonly enlarged at the tip
into a miniature club. The antennae of the larger moths are commonly
feathery or are long and slender, tapering gradually toward the tip.
[Illustration: Butterfly wing scales, magnified.
(From Holland)]
The characteristic features that distinguish a moth from a butterfly
are well illustrated in the plate opposite page 49, which shows one of
the largest and most beautiful moths in the world. It is the Cynthia
moth. As may be seen, the newly emerged moth is resting upon the
silken cocoon in which it spent its period as a pupa or chrysalis.
This cocoon was attached by the caterpillar to the twig from which it
hangs at the time it spun the cocoon. The feathered antennae, the
hairy legs, the thick thorax, and large abdomen--all show very clearly
in this side view of the moth. As will be seen, the wings are large
and very suggestive of those of a butterfly and have the
characteristic eye-spots toward the tip and the crescent marks in the
middle, which are so often found on the wings of the larger moths.
Some of these large moths on cloudy days occasionally fly during
daylight and, by the uninitiated, they are often mistaken for large
butterflies. One who will notice their structure, however, will
readily see the characteristic features of the moth.
In the caterpillar stage, there are no hard and fast differences
between the larvae of butterflies and those of the higher moths. In
each case, the insect consists of a worm-like body, having a small
head provided with biting jaws and simple eyes or ocelli. Back of the
head are the three rings of the thorax, each of which bears a pair of
jointed legs. Back of these three rings there are a considerable
number of other body rings making up the abdomen, on the middle of
which there are commonly four or five pairs of fleshy prolegs, not
jointed but furnished at the tip with fine claws. At the hind end of
the body there is another pair of prolegs similar in structure.
THE SCENTS OF BUTTERFLIES
Many students of American butterflies have occasionally mentioned the
fact that certain species seem to give off a distinct scent which has
frequently been spoken of as a pleasing fragrance, suggesting
sandalwood or some other aromatic odor. The general subject as
exemplified by butterflies of other lands has been studied for many
years by Fritz Müller; and certain English entomologists have paid
considerable attention to it. A translation of the Müller publications
and an excellent summary of our present knowledge of the subject is
published in Dr. Longstaff's book on butterfly hunting.
The odors given off by butterflies are divided into two principal
kinds, namely: first, those which are repulsive to the senses of man,
and evidently for the purpose of protecting the butterflies from birds
and other vertebrate enemies--these are found in both sexes; second,
those which are evidently for the purpose of sexual attraction and
confined to the male butterflies--these scents are usually attractive
to the senses of man.
[Illustration: Androconia from wings of male butterflies]
The aromatic scents of the second group are generally produced by
means of certain scales or hairs of many curious forms, which are
scattered over the surface of the wings or are placed within certain
special pockets, generally near the borders of the wings. These scales
or hairs are called androconia. Some of them much magnified are
represented in the picture above.
Our knowledge of the scents given off by American butterflies is very
fragmentary, and it is highly desirable that many more observations
should be made upon the subject. If collectors generally would make
careful notes, both in the field and upon the freshly killed
butterflies at home, we ought soon to be able greatly to extend our
knowledge. By holding the butterfly with a pair of forceps, one can
often determine whether the fragrance is emitted. It is often helpful
also to brush the hairs or tufts where the androconia are attached,
using a small, dry camel's hair brush for the purpose.
BUTTERFLY MIGRATIONS
Migration seems to be a general instinct in the animal world,
developed when a species becomes enormously abundant. At such times
this instinct apparently overcomes all others and the creatures move
on regardless of obstacles and conditions that may mean certain death
to the vast majority. Such migrations among mammals have often been
recorded, one of the most notable examples being that of the little
lemmings which migrate at periodical intervals in a way which has
often been described. Among the insects such migrations have been
frequently noticed, and the phenomenon has apparently been observed
oftener among the butterflies than in any other group. Entomological
literature during the last hundred years contains a great many records
of enormous flights of butterflies over long distances, extending even
from Africa into Europe or from one part of America to another far
remote. As such migration is likely to happen whenever a species
becomes extremely abundant it probably is Nature's way of providing
for an extended food supply for the succeeding generations. That it
results in the death of the great majority of the migrants is
doubtless true, but it must lead to vast experiments in extending the
geographic area inhabited by these species. Numerous examples of such
migrating swarms will be found in the pages of this little book. (_See
plates, pages 17,48-49, 160._)
[Illustration: _Photographed from life by A. H. Verrill_
_See page 12_
SWALLOWTAIL BUTTERFLY JUST OUT OF ITS CHRYSALIS.
THE CHRYSALIS SKIN BELOW]
[Illustration: _See page 72_
TIGER SWALLOWTAIL]
[Illustration: _Photographed from life_ _See page 7_
THE HAMMOCK CATERPILLAR ON ITS HAMMOCK]
The migrations thus considered are only exceptional occurrences. There
is, however, a regularly recurring annual migration on the part of
some butterflies which is also a phenomenon of extraordinary interest.
The most notable example is that of the Monarch which apparently
follows the birds southward every autumn and comes northward again in
spring. There is much evidence to indicate that in some slight degree
other butterflies have a similar habit, although the present
observations are inadequate to determine to what extent this habit has
become fixed in most of these species.
HIBERNATION OR WINTER LETHARGY
The ways in which butterflies spend the winter are always of peculiar
interest to the naturalist. Here are creatures with four distinct
stages of existence, each of which has the possibility of carrying the
species through the season of cold. It is necessary to learn for each
insect which stage has been chosen for the purpose, and if possible to
find the reasons for the choice.
As a rule the related members of a group are likely to hibernate in a
similar stage. Thus most of the Swallowtails pass the winter as
chrysalids while practically all the Angle-wings pass the winter as
adults. This rule, however, has many exceptions, for one will often
find closely related species which differ in the stage of hibernation.
As one would expect, the conditions of hibernation vary greatly with
the latitude. In the severe climate of the far north the conditions
are likely to be more uniform than in the South where the milder
climate permits greater variation to the insect. In some cases where a
butterfly hibernates in only one stage in Canada it may pass the
winter in two or more stages in Alabama or Florida.
In many other orders of insects the egg is a favorite stage for
hibernation. Even in the closely related moths it is often chosen by
many species, but comparatively few butterflies pass the winter in the
egg stage. The little Bronze Copper may serve as one example of this
limited group.
The conditions as to hibernation by the larvae of butterflies are very
different from those of the egg. It has been estimated that probably
half of all our species pass the winter in some stage of caterpillar
growth. This varies all the way from the newly hatched caterpillar
which hibernates without tasting food to the fully grown caterpillar
which hibernates full fed and changes to a chrysalis in spring without
eating anything at that time. A large proportion, however, feed both
in fall and spring, going through the winter when approximately half
grown.
The Graylings and the Fritillaries are typical examples of butterflies
which hibernate as newly hatched larvae. The eggs are laid in autumn
upon or near the food plants and the caterpillars gnaw their way out
of the shells and seek seclusion at once, finding such shelter as they
may in the materials on the soil surface. In spring they begin to feed
as soon as the weather permits and complete their growth from then
on.
The half-grown caterpillars may hibernate either as free creatures
under boards, stones, or in the turfy grass, or they may be protected
by special shelters which they have provided for themselves in their
earlier life. In the case of the latter each may have a shelter of its
own or there may be a common shelter for a colony of caterpillars.
Among the examples of those hibernating in miscellaneous situations
without special protection the caterpillars of the Tawny Emperor, the
Gray Emperor, the Pearl Crescent, and some of the Graylings are
examples. Among those which hibernate in individual shelters the
Sovereigns, among which our common Viceroy is most familiar, are good
examples. Among those which hibernate in a tent woven by the whole
colony for the whole colony the Baltimore or Phaeton butterfly is
perhaps the best example.
The caterpillars that hibernate when full grown may be grouped in a
way somewhat similar to those which are half grown. Many species
simply find such shelter as they may at or near the soil surface. The
Clouded Sulphur is a good example of these. Others pass the winter in
individual shelters made from a leaf or blade. Several of the larger
Skippers are good examples of this condition. So far as I know none of
our species pass the winter in colonial shelters when full grown.
It would be natural to suppose that the great majority of butterflies
would be likely to hibernate in the chrysalis state. Here is a quiet
stage in which the insect is unable to move about or to take any food,
in which it seems entirely dormant and as a rule is fairly well hidden
from the view of enemies. We find, however, that only a rather small
proportion of our butterflies has chosen this stage for survival
through the winter. The most conspicuous examples are the
Swallowtails, nearly all of which hibernate in the chrysalis stage.
Other examples are the various Whites, the Orange-tips, and isolated
species like the Wanderer, and the Spring Azure and the American
Copper. Practically all the butterflies that pass the winter as
chrysalids have a silken loop running around near the middle of the
body which helps to hold them securely through the long winter months.
Apparently none of those chrysalids which hang straight downward are
able to survive the winter.
An adult butterfly seems a fragile creature to endure the long cold
months of arctic regions. Yet many of our most beautiful species
habitually hibernate as adults, finding shelter in such situations as
hollow trees, the crevices in rocks, the openings beneath loose bark
or even the outer bark on the under side of a large branch. It is
significant that most of the adult-wintering Angle-wings are northern
rather than southern species, some of them being found in arctic
regions practically around the world. One of the few southern forms
that hibernates as an adult is the Goatweed Emperor.
These examples are all cases of true hibernation in a lethargic
condition. There are certain butterflies, however, which pass the
winter as adults that remain active during this period. Obviously this
is impossible in latitudes where the winter is severe, and it involves
migration to a warmer climate. The one notable illustration of this is
the Monarch butterfly which apparently flies southward to the Gulf
states at least and there remains until spring, when individuals come
north again. The southward migration may be begun in Canada when the
butterflies gather together in enormous flocks that remind one of the
gathering of the clans with the migrating birds. This is one of the
least understood of insect activities but it has been observed so
often and over so long a period of years that there seems to be no
questioning the general habit.
Like everything else in relation to living things there are numerous
variations in the prevailing modes of hibernation. In the case of many
species one can find combinations of two or more stages in which the
winter is passed. Probably if we could observe with sufficient care we
might be able to find somewhere examples of almost any conceivable
double combination--as egg with larva or chrysalis or adult--the
insect hibernating in two of these stages. Many examples are known in
which both chrysalis and adult of the same species pass the winter and
also of those in which young and well-grown larvae pass the winter. As
one would expect, the conditions as to such combinations are likely to
be more variable in southern than in northern regions.
Notwithstanding all the attention which has been paid to butterfly
life-histories there is still some uncertainty in regard to the
hibernation of many of our species. One of the most interesting series
of observations which a young naturalist could undertake would be to
learn positively how each species of butterfly in his locality passes
the winter.
AESTIVATION OR SUMMER LETHARGY
In some species of butterflies there is a special adaptation to
passing through the hottest part of the summer season in a state of
lethargy which is suggestive of the torpor of the hibernating period.
This phase of butterfly existence has not been extensively studied and
there are indications that it exists more generally than has been
commonly supposed. It has been noticed even in northern New England
that some of the Angle-wings seek shelter and become lethargic during
August. Apparently this is an adaptation to single broodedness,
helping to carry the species through the year without the exhaustion
incident to the continued activity of the butterfly.
In more southern regions, especially in the hot, dry climates where
vegetation withers in midsummer, it is well known that some
caterpillars become lethargic, remaining inactive until the fall rains
start vegetation into growth. The Orange-sulphur butterfly is a good
example of this.
This summer lethargy offers excellent opportunity for careful study.
Any observer who finds a butterfly hidden away in summer under boards,
the bark of a tree, or in a stone pile should look carefully to see
what species it is and how the butterfly behaves. Such observations
should be sent to the entomological journals in order that our
knowledge of the subject may be increased.
FEIGNING DEATH
The fact has long been noticed that various butterflies have the habit
at times of feigning death and dropping to the ground where they may
lie motionless for a considerable period. This habit is most easily
observed in some of the Angle-wings, especially those which hibernate
as adults. Those species have the under surfaces of their wings
colored in various bark-picturing patterns and apparently live
through the winter to some extent, resting beneath the bark of large
branches or upon the trunks of trees. Many of them also secrete
themselves in hollow trees or beneath loose bark or in board piles or
stone walls. It is probable, however, that during the long ages when
these insects were adapting themselves to their life conditions,
before man interfered with the natural order and furnished various
more or less artificial places for hibernation, these butterflies
rested more generally upon the under side of branches than they do
now.
Even in warm weather when one of these butterflies is suddenly
disturbed it is likely to fold its legs upon its body and drop to the
ground, allowing itself to be handled without showing any signs of
life. This habit is doubtless of value, especially during hibernation
or possibly during the summer lethargy or aestivation, the latter a
habit which may be more general among these butterflies than is now
supposed. As the insect lies motionless upon the ground it is very
likely to blend so thoroughly with its surroundings that it becomes
concealed, and any bird which had startled it from the branch above
would have difficulty in finding it.
Some very interesting observations have been made upon the
death-feigning instincts of various other insects, especially the
beetles. But no one so far as I know has yet made an extended study of
the subject in relation to our American butterflies. It is an
excellent field for investigation and offers unusual opportunities for
photographic records. One of the pictures opposite page 32 shows a
photograph which I took of a Mourning Cloak as it was thus playing
'possum. This species exhibits the instinct to a marked degree.
COLORATION
The caterpillars of butterflies and moths form a large part of the
food of insect-eating birds. These caterpillars are especially adapted
for such a purpose and in the economy of nature they play a very
important part in keeping alive the feathered tribes. During the long
ages through which both birds and insects have been developing side by
side, there have been many remarkable inter-relations established
which tend on the one hand to prevent the birds from exterminating the
insects and on the other to prevent the insects from causing the birds
to starve. The most important of these, so far as the caterpillars are
concerned, are the various devices by which these insects protect
themselves from attack, by hiding away where birds are not likely to
find them, by clothing their bodies with spiny hairs, by other methods
of rendering themselves distasteful, or by various phases of
concealing coloration. On the whole, the examples of the latter are
not so numerous or so easily found in the case of the larvae of
butterflies as in those of moths.
Perhaps the basal principle of concealing coloration is the law of
counter-shading, first partially announced by Prof. E. B. Poulton, and
later much more elaborately worked out by Mr. Abbott H. Thayer, and
discussed at length by Mr. Gerald H. Thayer in his remarkable volume,
"Concealing Coloration in the Animal Kingdom." The law of
counter-shading is tersely stated in these words: "Animals are painted
by nature darkest on those parts which tend to be most lighted by the
sky's light and _vice versa_." As this law works out on most animals
that live on or near the ground, the upper part of the body exposed
to the direct light from above is dark; and the under part, shut off
from the upper light and receiving only the small reflection from
below, is enough lighter to make the appearance of the creature in its
natural environment of a uniform tone from back to breast.
Nearly all caterpillars illustrate this law of counter-shading. If
they are in the habit of feeding or resting with their feet downward
the back will be darker and the under side lighter, but if they are in
the habit of feeding or resting in the opposite position these color
tones will be reversed. One can find examples of such conditions
almost any summer's day by a little searching of trees or shrubs.
This law of counter-shading, however, is really only the basis for the
coloration of caterpillars or other animals. It tends, chiefly, to
make the creature appear as a flat plane when seen from the side, and
may be said in a way to prepare the canvas upon which Nature paints
her more distinctive pictures. A great many examples of color markings
that tend to conceal the caterpillar amid its natural surroundings may
be found by any one who will study the subject and it offers one of
the most interesting fields for investigation. The chapter on
caterpillars in the above-mentioned book by Mr. Thayer should serve as
a starting point for any one taking up the subject.
Butterflies differ from caterpillars and from most other animals in
the fact that their coloring is chiefly shown upon the flat surfaces
of the wings. Consequently, there is less opportunity for the various
phases of counter-shading which is so commonly shown in the larger
caterpillars. The bodies of nearly all butterflies do exhibit this
phenomenon, but these bodies are relatively so small that
counter-shading plays but a little part in the general display.
Upon the outstretched membranes of the butterflies' wings Nature
through the long ages of development has painted a great variety of
pictures. Those which tend to protect the insect by concealment amid
its surroundings are most commonly spread on the under surface of the
wings. Especially is this true in the case of those species which pass
the winter as adults or which have the habit of resting upon the bark
of trees, the sides of rocks, or the surface of the ground. We here
find some of the most interesting examples of obliterative coloring
that occur in nature. Some butterflies have taken on the look of tree
bark, others the sombre appearance of weathered rocks, while still
others are painted with the images of flowerets and their stems.
_Dazzling and Eclipsing Colors_
Many of the butterflies, especially the Angle-wings, which are marked
on the under surface in various protective colors, are admirable
examples of that phase of animal coloring which is spoken of as
_dazzling coloration_. This is apparently one of the most important
protective devices to be found in Nature and the validity of it is now
generally conceded by naturalists. One phase of it, which may be
called eclipsing coloration, seems to have been first definitely
formulated by the late Lord Walsingham, a famous English entomologist
who enunciated it in an address as president of the Entomological
Society of London. The most significant paragraphs in that address
were these:
"My attention was lately drawn to a passage in Herbert Spencer's
'Essay on the Morals of Trade.' He writes: 'As when tasting different
foods or wines the palate is disabled by something strongly flavored
from appreciating the more delicate flavor of another thing afterward
taken, so with the other organs of sense a temporary disability
follows an excessive stimulation. This holds not only with the eyes in
judging of colors, but also with the fingers in judging of texture.'
"Here, I think, we have an explanation of the principle on which
protection is undoubtedly afforded to certain insects by the
possession of bright coloring on such parts of their wings or bodies
as can be instantly covered and concealed at will. It is an undoubted
fact, and one which must have been observed by nearly all collectors
of insects abroad, and perhaps also in our own country, that it is
more easy to follow with the eye the rapid movements of a more
conspicuous insect soberly and uniformly colored than those of an
insect capable of changing in an instant the appearance it presents.
The eye, having once fixed itself upon an object of a certain form and
color, conveys to the mind a corresponding impression, and, if that
impression is suddenly found to be unreliable, the instruction which
the mind conveys to the eye becomes also unreliable, and the rapidity
with which the impression and consequent instruction can be changed
cannot always compete successfully with the rapid transformation
effected by the insect in its effort to escape."
Lord Walsingham then goes on to suggest that this intermittent play of
bright colors probably has as confusing effect upon birds and other
predaceous vertebrates as upon man; and that on this hypothesis such
colors can be accounted for more satisfactorily than upon any other
yet suggested. Since then the significance of this theory has been
repeatedly pointed out by Professor Poulton, Mr. Abbott H. Thayer, and
various other authorities upon animal coloring. The terms _dazzling_
and _eclipsing_ have been applied to the phenomenon.
Shortly after Lord Walsingham propounded this theory I called
attention [A] to its fitness in explaining some of the most interesting
color phases shown by American insects, notably the moths and locusts
which have brilliantly colored under wings and protectively colored
upper wings.
[A] _Popular Science Monthly_, 1898, "A Game of Hide and Seek."
Reprinted in the _Insect World_, 1899.
The animals of the north show numberless color phases of interest. One
of the most curious of these is exhibited by several families of
insects in which the outer wings are protectively colored in dull hues
and the under wings brightly colored. For example, there are many
species of moths belonging to the genus Catocala found throughout the
United States. These are insects of good size, the larger ones
measuring three inches in expanse of wings, and the majority of them
being at least two thirds that size. Most of them live during the day
on the bark of trees, with their front wings folded together over the
back. The colors and markings of these wings, as well as of the rest
of the exposed portions of the body, are such as to assimilate closely
with the bark of the tree upon which the insect rests. In such a
situation it requires a sharp eye to detect the presence of the moth,
which, unless disturbed, flies only at night, remaining all day
exposed to the attacks of many enemies. Probably the most important of
these are the birds, especially species like the woodpeckers, which
are constantly exploring all portions of the trunks of trees.
The chief beauty of these Catocalas, as they are seen spread out in
the museum cabinet, lies in the fact that the hind wings, which, when
the moth is at rest in life, are concealed by the front ones, are
brightly colored in contrasting hues of black, red, and white in
various brilliant combinations. These colors, in connection with the
soft and blended tones of the front wings, make a very handsome
insect.
It is easy to see that when one of these Underwing Moths is driven to
flight by a woodpecker or other bark-searching bird it would show
during its rapid, irregular flight the bright colors of the under
wings which would be instantly hidden upon alighting and the very
different coloring of the upper wings blending with the bark would be
substituted. Consequently, the bird would be very likely to be baffled
in its pursuit.
_Coloration of Locusts_
On the rocky hills and sandy plains of New England there are several
species of grasshoppers or locusts that also illustrate these
principles. If you walk along a strip of sandy land in summer, you
start to flight certain locusts which soon alight, and when searched
for will be found closely to assimilate in color the sand upon which
they rest. On a neighboring granite-ribbed hill you will find few if
any of this species of locust, but instead there occur two or three
quite different species, which when at rest closely resemble the
lichen-covered rocks. This resemblance is very striking, and is found
in all stages of the insect's existence. If now you go to a lowland
meadow, still another color phase will be found to prevail--the green
grass is swarming with the so-called "long-horned" grasshoppers,
which are green throughout with linear bodies, and long, slender legs
and antennae.
Each of these three groups of insects is adapted to its particular
habitat. All are constantly persecuted by birds, and have been so
persecuted for unnumbered ages in the past. In every generation the
individuals have varied, some toward closer resemblance to
environment, others in an opposite direction. The more conspicuous
insects have been constantly taken, and the least conspicuous as
constantly left to reproduce. Were the three groups to change places
to-day, the green grasshoppers from the meadows going to sandy
surfaces, the sand-colored locusts going to rocky hills, and the
"mossbacks" from the hills to the lowland meadows, each would become
conspicuous, and the birds would have such a feast as is seldom spread
before them.
The species living on sand and rocks are often "flushed" by birds.
Those which flew but a few feet would be likely to be captured by the
pursuing bird; those which flew farther would stand a better chance of
escaping. Similarly, those which flew slowly and in a straight line
would be more likely to be caught than those which flew rapidly and
took a zigzag course. As a consequence of the selection thus brought
about through the elimination of those which flew slowly along the
straight and narrow way that led to death, you will find that most
locusts living in exposed situations when startled fly some distance
in a rapid, zigzag manner.
But still another element of safety has been introduced by some
species of these locusts through the adoption of the color tactics of
the Catocala moths. The under wings of the common Carolina locust--the
species most abundant along the highway--are black, bordered with
yellowish white. The base of the hind wings of a related species
living on the Western plains is bluish, while in the large
coral-winged locust of the Eastern states the hind wings are red,
bordered with black. In nearly all of the species of these locusts
frequenting open localities where they are liable to disturbance by
birds or other animals, the hind wings exhibit contrasting colors in
flight. Most of them also fly in a zigzag line, and alight in a most
erratic manner. Many times I have had difficulty in determining the
exact landfall of one of these peculiar creatures, and I believe Lord
Walsingham's suggestion is well exemplified in them. (_See page 33._)
The most famous example of a combination of this dazzling coloring of
the upper wing surface with a definite protective coloring of the
under wing surface is the Kallima butterfly which is illustrated in
almost every book dealing with animal coloration. The under wing
surface bears a striking resemblance to a leaf and the hind wings
project to form a tail which looks like the petiole of the leaf, and
there is also a mark running across the wings which mimics the midrib.
When the butterfly is flying the brilliant colors of the upper surface
are visible, but when it alights these are instantly replaced by the
sombre tone of the under surface, so that apparently the insect
completely disappears and in its place there is only a leaf attached
to a branch in a most natural position. In Dr. Longstaff's book there
is an illustration of another tropical butterfly, _Eronia cleodora_,
which resembles on its under surface a yellow disease-stricken leaf
but on its upper surface gives a brilliant combination of black and
white. This insect alights upon the leaves which it resembles and is
a striking example of both dazzling and mimicking coloration.
Many of our own butterflies, notably the Angle-wings, are excellent
examples of a similar combination. In flight they reveal conspicuous
colors which are instantly hidden upon alighting and then one only
sees the bark-like or dead leaf-like under surface as may be seen in
the plate opposite pages 160-161. The iridescence upon the upper wing
surface of many butterflies, whose under wing surface is colored in
concealing tones, is doubtless also of great use to the insect in a
similar way. There is a splendid opportunity here for some observer to
study this phase of butterfly activity and to get photographs of the
insects amid their natural surroundings.
In their book upon "Concealing Coloration" the Messrs. Thayer have
called attention to many interesting phases of dazzling coloration.
They show that bright marks like the eye-spots or ocelli, which form
so prominent a feature on the wing surfaces of many butterflies,
really helped to conceal the insect amid its natural surroundings, by
drawing the eye away from the outlines of wings and body so that the
latter tend to disappear. Their discussion of this subject opens up
another vast field for outdoor observations of absorbing interest, in
which there is great need for many active workers.
[Illustration: _See page 23_
BUTTERFLY FEIGNING DEATH, HANGING TO BARK BY ONE FOOT]
[Illustration: _See page 17_
BUTTERFLY IN HIBERNATING POSITION]
[Illustration: Caterpillar feeding upon leaf of milkweed
Caterpillar hung up for the change to the chrysalis
The transition stage
The Chrysalis
THE MONARCH BUTTERFLY: CHANGE FROM CATERPILLAR TO CHRYSALIS.
Photographs from life. (_See pages 8-10, 233_)]
[Illustration: Chrysalis showing butterfly ready to emerge
The empty chrysalis
Butterfly just out of chrysalis
Side view a little later
THE MONARCH BUTTERFLY: THE CHANGE FROM CHRYSALIS TO ADULT.
Photographs from life (_See pages 10-13, 235_)]
[Illustration: _See page 30_
THE CAROLINA LOCUST
Above, with wings expanded as in flight]
SELECTIVE COLOR SENSE
One who collects the Underwing moths soon discovers that the light
colored species which resemble the bark of birch trees are likely to
be found upon the trunks of those trees, and that the dark colored
kinds which resemble the bark of maple trees are likely to be found
upon the trunks of these. Obviously, were this not true the protective
coloring would avail but little and it is evident that these moths are
able to select a background which is of advantage in helping to
conceal them.
There is much evidence to show that in a similar way the butterflies
are able by means of a well-developed color sense to select the places
where they alight. One of the most notable examples is that of a South
American species, _Peridromia feronia_. This is a silvery gray
butterfly which alights head downward upon the bark of certain palm
trees that have silvery gray stems and remains there with its wings
fully expanded so that it utilizes the background in much the same way
that the Underwing moths do. "When disturbed they will return to the
same tree again and again."
One who will observe the habits of our Angle-wings and other
butterflies which have obliterative coloring of the under wing surface
can easily learn that these insects select rather carefully the places
where they alight. It will be found that as a rule each species
utilizes a background that blends with its own coloring. It is
probable that this habit is much more common in other groups of
butterflies than has been realized. Much evidence of this sort has
been collected regarding the butterflies of Europe and other
countries, as well as near our own borders in America.
WARNING COLORATION AND MIMICRY
The colors of a great many animals, including a considerable
percentage of American butterflies and their larvae, have been
commonly explained by the theory of _warning colors_. According to
this theory animals which were for any reason not edible by birds and
mammals have developed various striking combinations of color such as
black and yellow, red and black, or black and white, in order to
advertise to their foes their inedible qualities. This theory has been
very generally accepted by naturalists and will be found expounded at
length in many books published during the last quarter century.
The whole subject of the validity of warning coloration has recently
been brought up for reconsideration by the illuminating investigations
of Mr. Abbott H. Thayer and discussed at length in the book upon
"Concealing Coloration" already mentioned. In an appendix to this book
dated 1908 Mr. Thayer states that he no longer holds the belief that
"there must somewhere be warning colors." He has convincingly shown
that a large proportion of the animals which were supposed to be
examples of this theory are really illustrations of concealing
coloration. But there yet remain various facts which have been
conclusively proven that apparently require the theory of warning
colors to explain them. Here is another field in which there is a real
need for much careful investigation under conditions that are rigidly
scientific.
Along with the theory of warning coloration the theory of _mimicry_
has been propounded. According to this if a butterfly in a given
region shows warning coloration, having developed such coloration
because it is distasteful to birds and mammals, it may be mimicked by
another butterfly in the same region belonging to another group, the
latter butterfly being edible, but benefiting by its resemblance to
the distasteful species, because birds or mammals mistake it for the
latter and do not attempt to catch it. The most notable example of
such mimicry in North America is that of the Monarch butterfly, which
is supposed to be the distasteful species, and the Viceroy butterfly,
which is supposed to mimic it. Several other instances of mimicry are
found among our own butterflies, while in South America, Africa, and
Asia there are numberless examples.
HELIOTROPISM
It has long been known that the green surfaces of plants respond to
the stimulus of the sun's rays in a most remarkable manner. This
response has commonly been called _heliotropism_ and it has been
carefully studied by botanists all over the habitable world. More
recently, the fact has been observed that many animals respond in
certain definite ways to the stimulus of direct sunshine and the same
term has been applied in this case. Very little attention has been
given to the subject of heliotropism until within a few recent years.
But the observations which have been made by Parker, Longstaff, Dixey,
and others open up a most interesting field for further observation.
An admirable summary of our present knowledge of the subject has been
published by Dr. Longstaff in his book "Butterfly Hunting in Many
Lands."
One of the earliest observations upon this subject was that published
in my book "Nature Biographies" which appeared in June, 1901,
concerning the habit in the Mourning Cloak: "On a spring-like day
early in November (the 8th) I came across one of these butterflies
basking in the sunshine upon the ties of a railway track. It rested
with its wings wide open. On being disturbed, it would fly a short
distance and then alight, and I was interested to notice that after
alighting it would always turn about until the hind end of its body
pointed in the direction of the sun, so that the sun's rays struck its
wings and body nearly at right angles. I repeatedly observed this
habit of getting into the position in which the most benefit from the
sunshine was received, and it is of interest as showing the extreme
delicacy of perception toward the warmth of sunshine which these
creatures possess."
A little later, some very elaborate observations were made upon this
habit of the Mourning Cloak by Prof. G. H. Parker of Harvard
University. Professor Parker noticed that during the warm spells in
winter the butterflies came out of their hiding places and after
alighting, always placed themselves with their heads away from the
direction of the sun and their bodies lying nearly at right angles to
the sun's rays. By experiment, he found that they adjusted themselves
to this position as soon as they were fully exposed to direct
sunshine, even if at the time of alighting they were in a shadow. He
found that this movement was a reflex action through the eyes, for
when the eyes were blinded no such adjustment took place. He called it
_negative heliotropism_.
Dr. Longstaff uses the term _orientation_ for this adjustment of the
butterfly to the sun's rays and he finds it is a very general habit,
especially with the Angle-wings, for the butterfly thus to orient
itself after alighting, in such a way that the hind end of the body
points toward the sun. This occurs not only with those species which
keep their wings spread open when they alight but also with those in
which the wings are closed together and held in a vertical position on
alighting.
Various explanations of this phenomenon have been offered but
apparently none of them are yet generally accepted. Were the habit
confined to butterflies like the Mourning Cloak, it would seem easy to
prove that a main advantage was found in the benefit derived from the
heat rays of the sun. Were it confined to those species which always
fold their wings on alighting, it would seem easy to believe that it
was a device for reducing the shadow cast by the insect to its lowest
terms. It has also been suggested that the habit is for the purpose of
revealing to the fullest extent the markings of the butterfly.
Evidently there is here an ample field for further investigation
before definite conclusions are reached.
LIST AND SHADOW OBSERVATIONS
Another field for most interesting studies upon the habits of living
butterflies has been opened up by the very interesting discussion of
_list and shadow_ in Colonel G. B. Longstaff's fascinating book,
"Butterfly Hunting in Many Lands." He there summarizes his numerous
observations upon butterflies in various localities which he has seen
to lean over at a decided angle when they alight. He defines "_List_"
as "an attitude resulting from the rotation of the insect about its
longitudinal axis, as heliotropism results from a rotation about an
imaginary vertical axis at right angles to this." The name is adapted
from the sailors' term applied to a vessel leaning to one side or
another in a storm.
Apparently this interesting habit was first called to the attention of
European entomologists by an observation of Colonel C. T. Bingham
made in 1878, but not published until long afterward. The observation
was this:
"The _Melanitis_ was there among dead leaves, its wings folded and
looking for all the world a dead, dry leaf itself. With regard to
Melanitis, I have not seen it recorded anywhere that the species of
this genus when disturbed fly a little way, drop suddenly into the
undergrowth with closed wings, and invariably lie a little askew and
slanting, which still more increases their likeness to a dead leaf
casually fallen to the ground."
Long before this was printed, however, a similar habit had been
observed by Scudder in the case of our White Mountain butterfly
(_Oenis semidea_). But this species is so exceptional in its habitat
that the habit seems to have been considered a special adaptation to
the wind-swept mountain top. The possibility of its being at all
general among the butterflies in lowlands seems to have been
overlooked.
The observations recorded by Longstaff relate chiefly to various
members of the Satyrid group. For example, a common Grayling, _Satyrus
semele_, was watched many times as it settled on the ground. As a rule
three motions are gone through in regular sequence: the wings are
brought together over the back; the forewings are drawn between the
hind wings; the whole is thrown over to right or left to the extent of
thirty, forty, or even fifty degrees.
This habit, of course, is of advantage to the insect. It seems
possible that the advantage might be explained in either of two ways:
first, the leaning over on the ground among grasses and fallen leaves
might help to render the disguising coloration of the insect more
effective, the large ocelli serving to draw the eye away from the
outline of body and wing; second, the listing of the butterfly toward
the sun tends to reduce the shadow and to hide it beneath the wings.
There is no doubt that when a Grayling butterfly lights upon the
ground in strong sunshine the shadow it casts is more conspicuous than
the insect itself and the hiding of this might be of distinct
advantage in helping it to escape observation. It is significant that
in England the butterflies observed appear to lean over more
frequently in sunshine than in shade. An observation of Mr. E. G.
Waddilove, reported by Colonel Longstaff, is interesting in this
connection:
"A Grayling settled on a patch of bare black peat earth, shut up its
wings vertically, and crawled at once some two yards to the edge of
the patch to where some fir-needles, a cone or two, and a few brittle
twigs were lying, and then becoming stationary threw itself over at an
angle of some forty-five degrees square to the sun. It thus became
quite indistinguishable from its surroundings."
Apparently, some of the Angle-wings may have the same habit, for in
Barrett's "Lepidoptera of the British Islands," there is a note in
regard to _Grapta C-album_ to the effect that it is fond of sunning
itself in roads, on warm walls, or on the ground upon dead leaves in
sheltered valleys. "Here, if the sun becomes overclouded, it will
sometimes close its wings and almost lie down, in such a manner that
to distinguish its brown and green marbled under side from the dead
leaves is almost impossible."
Here is a most fascinating opportunity for American observers to
determine definitely the facts in regard to our numerous species of
butterflies that may show this habit. An observer with a reflex type
of camera might easily be able to get pictures that would be of great
value in helping to determine the principal facts in regard to the
subject. Our common Graylings and numerous species of Angle-wings are
so abundant and easily observed that they offer splendid opportunities
to any one who will undertake a serious study of the subject.
PARASITIC ENEMIES
All three of the earlier stages of butterflies--egg, larva, and
chrysalis--are subject to attack by various parasitic insects which
develop at the expense of the host. Such parasites are probably the
most important check upon the increase of butterflies, and along with
birds, mammals, and bacterial diseases, they help to keep up that
balance of nature which in the long run maintains a surprising
uniformity in the numbers of each kind of butterfly.
For the most part these insect parasites are small four-winged flies,
although many of them are two-winged flies. In either case the life
stages show a series of changes much like those of the butterflies
themselves. Each parasite exists first as an egg, second as a larva,
third as a pupa, and fourth as an adult fly. The larval stage,
however, is simply that of a footless grub which lives within the body
of its victim absorbing its life blood and gradually killing it.
The parasites of butterfly eggs are legion. They are tiny flies whose
life-story in briefest summary is this: The butterfly lays an egg. The
parasite fly finds this egg soon after it is laid, and pierces the
shell with her tiny, sharply pointed ovipositor and deposits inside of
the shell her own microscopic egg. This egg within the egg soon
hatches into a curious little larva that develops at the expense of
the contents of the butterfly egg shell, and soon absorbs the whole
of them. The parasite larva now changes to a pupa which a little later
changes again to an adult fly like the one that laid the parasite egg
in the beginning. Of course the butterfly egg never hatches into a
caterpillar.
One of the most interesting questions in regard to these egg parasites
is this: How does the tiny parasitic fly find the newly laid egg? One
would think that the proverbial search for a needle in a haymow would
be an easy task compared with that of a fly about as large as the head
of a pin finding a butterfly egg of similar size upon some part of one
of the millions of leaves upon the trees and shrubs in field and
forest. Yet the search is successful, as every one who has tried to
get caterpillars from eggs found out of doors will testify. On a later
page in this book, in connection with the story of the life of the
Mourning Cloak butterfly, I have recorded some observations upon the
little parasite which seemed to have been riding around upon the body
of the butterfly waiting for her to lay her eggs.
For one parasite upon the eggs of butterflies, there probably are
dozens that attack the caterpillars. A large proportion of the
butterfly larvae brought in from outdoors, especially those which are
half-grown or more, will yield not butterflies but parasites. This is
the experience of practically every one who attempts to rear these
insects, and it emphasizes the value of the advice that in order to
get fine specimens, it is desirable to rear them from eggs laid by
butterflies beneath netting or in cages.
The life-histories of the parasites that attack caterpillars vary
greatly. The simplest are those of the large Ichneumon flies: The
mother fly lays an egg beneath the skin of the caterpillar. The egg
hatches into a larva that absorbs the fatty parts of the body of the
caterpillar, gradually growing larger and larger until at last it
reaches a length of possibly an inch. By this time it is likely to
have absorbed so large a part of the inside of the caterpillar that
the latter dies. The parasite larva now changes to a pupa, either
inside or outside the skin of the caterpillar, and a little later
changes again to an adult Ichneumon fly.
[Illustration: Tachinid Parasite: _a_, fly; _b_, puparium,
magnified.]
In the case just given, one egg only was deposited within the skin of
the caterpillar. In many others, however, a large number of eggs may
be so deposited by a single fly. A special group of Ichneumon flies,
called the Microgasters, contains many parasites that have this
peculiarity. The Microgaster larvae on coming forth from the
caterpillar have the habit of spinning tiny cocoons within which they
change to pupae. By collecting some cabbage worms which are nearly
full grown, and keeping them in a glass jar one can generally get a
considerable number of these Microgaster cocoons and rear the flies
from them.
Another group of caterpillar parasites is still more minute. They are
called the Chalcid flies. Their life-histories are full of interest,
and might easily furnish opportunity for a long lifetime of study and
experiment. One is likely to get hundreds of these Chalcid flies from
a single caterpillar.
Another interesting group of parasites is that of the two-winged
Tachina flies (_see cut on this page_). The life-story of some of
these is comparatively simple: a buzzing fly, looking much like a
large housefly, lays a small whitish egg upon the skin of a
caterpillar. This egg is glued tightly and is large enough to be
readily seen by the unaided eye. It hatches into a tiny larva that
eats its way through the part of the shell glued to the caterpillar's
skin, and through the latter at the same time. So the newly hatched
Tachina larva finds itself in the body of its caterpillar host. It
lives there, absorbing the fatty juices around it until at last it
either kills or stupefies its unfortunate victim. It has then become
full grown as a larva, and its last larval skin hardens into a brown
pupa-case within which the little creature changes into a pupa. It may
or may not have burrowed through the skin of the caterpillar before
this happened. A little later the pupa changes to a Tachina fly which
breaks apart the pupa-case and flies out into the world.
It has lately been found, however, that many Tachinids have much more
complicated life-histories than this. I have already discussed some of
the more important of these in my book entitled, "Seeing Nature First"
(_pages 150-158_).
One can frequently rear parasites from the chrysalids of butterflies,
but in many cases it is probable that these began their parasitic
development in the caterpillars, which were able to change to
chrysalids before being killed. In some cases, however, the chrysalids
seem to be attacked, especially by certain Ichneumon flies.
REARING BUTTERFLIES FROM CATERPILLARS
There are few things in the world more interesting to watch than the
wonderful changes which a moth or butterfly goes through in the
course of its life. You find on a tree or shrub a worm-like
caterpillar. You take it in charge, placing it in a box or jar where
you can provide leaves for its food and soon it either spins around
itself a silken shroud, thus hiding from your sight, or else it simply
seems to change to a lifeless object without eyes or wings or legs,
unable to move about and motionless, save for a slight wriggle when
you touch it. Yet if you keep the shroud or the mummy-like object for
two or three weeks you are likely to see a beautiful moth come from
the shroud or a glorious butterfly break out of the mummy case. (_See
plate, page 49._) So you can get the realest kind of moving pictures
by simply bringing in the caterpillars that are easily found in
garden, field, and wood.
To collect these caterpillars it is only necessary to be provided with
a pair of sharp eyes and an empty coffee can or some other form of tin
box. Go out into the garden or along the borders of the woods. Look
carefully. If you see places where leaves have been eaten, search the
leaves near by and you are likely to find one or more of the
caterpillars that caused the injury. Transfer them to the box and take
them home with a few leaves of the food plant. There place them in
some form of vivarium, which simply means a box or cage in which you
can keep living creatures.
The most satisfactory cages for rearing caterpillars are those which
are open above so that there is not even a glass plate between the
observer and the insect. This kind of vivarium is easily made by using
a band of some sticky substance like the tree tanglefoot with which
trees are commonly banded, or a strip of sticky fly paper. Any wide
shallow box may be used by simply placing an inch-wide band of the
sticky material around the vertical sides near the top. The
caterpillars will be free to move all over the open box but they
cannot cross the band to escape. Fresh leaves are easily placed in the
open box and the withered ones removed.
The same plan may be adopted with wide glass jars, like the ordinary
battery jar. Choose a rather large one and smear the inner side near
the top with a band of sticky material. The caterpillars are thus
prevented from crawling out, but they are open to observation at all
times. (_See plate, pages 48-49._)
In the case of the caterpillars that change to butterflies no soil
need be placed in the bottom of the jar as these will attach their
chrysalids to the sides or to a stick or board which may easily be put
in. In the case of many caterpillars that change to moths, however, it
is desirable to place about two inches of soil in the bottom of the
jar. Then if the caterpillars are not cocoon spinners they can burrow
into the soil when they are ready to change to pupae.
Instead of applying the sticky material directly to the glass a strip
of sticky fly paper may be glued to it.
As a rule the butterfly caterpillar easiest to find lives upon
cabbages. Go into the garden and you are likely to see a dozen green
caterpillars upon as many cabbage plants. Bring in several of the
larger ones and place them in a vivarium with some fresh cabbage
leaves. In a few days some of them will be likely to fasten themselves
to the vertical sides of the vivarium and shed the caterpillar skin.
Each thus becomes a chrysalis. About ten days later this chrysalis
skin will break open and a white Cabbage butterfly will come out.
So your caterpillar goes through the four different stages of insect
life. It was first an egg laid upon the leaf by a butterfly; the egg
hatched into the caterpillar or larva; the larva changed to the
chrysalis; the chrysalis changed to the butterfly or adult insect.
One of the most satisfactory ways to rear the caterpillars of
butterflies is to get the females to lay their eggs upon the food
plant. In the case of many species this is not difficult. The simplest
way is to enclose the mother butterfly in a small gauze bag tied over
the branch of the food plant. If she has eggs ready to deposit she is
very likely to lay them under these conditions. After they are laid
the mother butterfly may be allowed to escape, but it is well to
replace the gauze protection as a safeguard against many sorts of
enemies which may destroy the eggs or the young caterpillars that
hatch from them. Another way is to enclose the butterflies with a twig
of the food plant in a glass jar, sealing it tight to prevent the
leaves from wilting. The butterfly is likely after she has quieted
down to lay her eggs upon the leaves. According to William G. Wright,
who speaks from his long experience with the butterflies of the West
Coast, these genera will lay their eggs on anything: Parnassius,
Argynnis, Euptoieta, Neonympha, and all members of the family
Satyridae. In these cases one can get the eggs by simply enclosing the
butterflies in glass jars or gauze nets without even the leaves of the
food plant. William H. Edwards found in his long experience that one
can get the eggs of practically all butterflies in confinement,
provided only the insects are sufficiently mature so that the eggs are
ready to be laid. He found that the cause of failure to get eggs from
many of the Fritillaries early in the season was that the eggs were
not mature and that from the same kinds of butterflies with which he
failed early in the summer he got plenty of eggs in September.
There is here a rich field for observation and experiment for every
naturalist who wishes to take up the study of butterflies. He can be
sure of the parentage of the caterpillars and can trace them from the
very moment of egg-laying through all their wonderful changes until
they become butterflies again.
PHOTOGRAPHING BUTTERFLIES
There is a famous old saying that to make hare stew it is first
necessary to catch your hare. So if one wishes to make perfect
pictures of butterflies it is first necessary to get the caterpillars.
For though caterpillars are not butterflies they are butterflies in
the making and they will show you most interesting stages in nature's
manufacture of these dainty and exquisite creatures. This is not,
however, the chief reason why the photographer should get them. He
will wish to make perfect pictures and in order to do this he must
have not only perfect specimens but living butterflies which are
willing to look pleasant while he makes comparatively long exposures
under conditions of light that he can control. If you catch a
butterfly outdoors and bring it in you will be likely to find that it
is by no means a docile subject. The sunlight shining through the
nearest window will be a call which you cannot counteract and your
butterfly will constantly respond to it in a most vexing manner. So
you must catch the butterfly young and take advantage of a brief but
docile period in their lives when they are willing to pose before your
camera in quite a remarkable manner. This is the period just after
the butterfly emerges from the chrysalis when its wings are fully
developed but before the tissues have hardened and the muscles in the
thorax are strong enough for flight. At this time the butterfly is
perfect, every scale is in its place and every spot of color is at its
best, and it will rest quietly upon a flower, leaf, or twig while you
adjust the camera and expose the plate. From one such specimen one can
get many pictures upon different flowers and with different angles of
view. (_See plates, pages 160, 225._)
In order to make admirable photographs of living butterflies it is by
no means necessary to have a regular photographic studio. If one has a
room lighted from the north or east one can arrange for exposure near
the window, using cardboard reflectors to make the light more even
from both sides. In such a situation one soon learns the exposure
periods required and can easily get many beautiful photographs.
A collection of prints of the butterflies of one's locality would be
one of the most interesting photographic exhibits that an amateur
could select. It is comparatively easy to get rather full sets showing
the life-histories of several of our larger species and such sets are
of course of especial interest. In the case of those caterpillars
which make nests upon the food plant, like the Painted Beauty larva
which remains for weeks feeding upon the leaves of the common wild
everlasting, the taking of the pictures of the different stages is
comparatively easy. One can keep the plant with the stem in water, and
get the caterpillar to change to the chrysalis, and emerge as the
butterfly, in the nest made from the flower heads and the upper
leaves.
[Illustration: _From a drawing by W. I. Beecroft_ _See page 59_
THE BLACK SWALLOWTAIL
Caterpillar, chrysalis and butterfly]
[Illustration: Two hundred Monarchs resting on one dead limb]
[Illustration: _Photographed by Craig S. Thomas_ _See pp. 16, 235_
"When a stick was thrown into the tree the air was full of
Monarchs"
A MIGRATION OF MONARCH BUTTERFLIES]
[Illustration: _See page 45_
THE IMPROVED OPEN VIVARIUM]
[Illustration: _From a photograph from life by A. H. Verrill._
_See page 14_
THE CYNTHIA MOTH AND THE COCOON FROM WHICH IT CAME]
BUTTERFLY COLLECTIONS
There are few groups in Nature which offer such advantages to the
collector as that of the butterflies. They are easily obtained, easily
preserved, and retain their beauty for a long period even under
exposure to strong light. They offer opportunities for serious study
in which one cannot only review the facts which others have already
discovered, but also hope to contribute something of value to the sum
of human knowledge.
The mistake most commonly made by beginners with butterflies, as with
other collections, is to undertake too much. Instead of starting on
the hopeless task of making a collection of the butterflies of the
world, it is much better to start with the intention of making a
collection of those of one's own town. In the latter case one can hope
soon to attain the desired end and then, if one wishes, it is a simple
matter to reach out and make a collection of the butterflies of the
state or even of the particular region in which the state is located.
The natural limitations for a collection in New England is to make a
collection of New England butterflies. There is a splendid example of
such a collection on exhibition in the museum of the Boston Society of
Natural History. This contains representatives of practically every
kind that has been collected in New England, and yet there are less
than a hundred species in all. So it is apparent that a local
collection should be attainable by any enthusiastic student and the
very fact that the number of species is limited adds interest and
satisfaction to the pursuit.
The main value of any collection of objects lies in the point of view
of the collector. The most natural point of view for a beginner is
that of the local fauna, as indicated in the previous paragraph. Such
a collection best serves as a basis for a study of the subject but it
may well lead to a broader field through some special phase of
scientific interest. Thus while it would be hopeless for most persons
to attempt a collection of the butterflies of the world it would be
entirely reasonable for one to start a collection of all the species
in the world of any given genus or tribe, and such a set of specimens
would soon come to possess decided scientific value. Or, instead of
the point of view of generic or family relationship, one could take
the point of view of special geographical distribution. Thus a
collection of all the butterflies found within a certain number of
degrees of the North Pole showing the circumpolar butterfly fauna
would have great scientific interest.
There are also various other points of view which could be followed in
making a collection. There are already in many of the museums of the
world collections of butterflies which illustrate the various phases
of true mimicry--the resemblance of one species to another in the same
region. This is a field in which one could spend a lifetime of
endeavor, and secure results of great value to the world of science.
An easier problem for most collectors in the United States would be a
collection made from the point of view of resemblance to environment,
including such examples as the Angle-wings that show a bark-like set
of marks on the under surface. Yet another point of view would be that
of hibernation, the making of a collection of all butterflies that
hibernate as adults.
These are only a few suggestions. There are many other phases of
butterfly life which could be utilized as the basis for interesting
collections. The important thing is to have a definite object in view
and to make the collection a basis for a real study of the subject, so
that the collector will not only be growing intellectually but will
also be making a real contribution to our scientific knowledge.
_Collecting Apparatus_
To collect and preserve butterflies in proper condition for study,
certain apparatus is necessary. Perhaps the first essential is the
collecting net for catching butterflies in the field. The simplest way
to obtain this is to buy it of the dealers in entomological supplies.
Nets in considerable variety and at various prices are offered in the
catalogues of these firms. One can make, however, a net at home with
little difficulty. One need only obtain an iron wire about one fifth
of an inch in diameter and bend it into a circular ring a foot or
fifteen inches wide, leaving the ends projecting at right angles to
the circle and having a blacksmith weld them together so as to form a
spur about four inches long. Now thrust this spur into some convenient
handle, such as a broomstick, and sew over the wire circle a bag of
mosquito netting, Swiss muslin, or some similar fabric. It is better
that this material be green or black rather than white.
After the butterflies are caught, they must be killed, so some form of
killing bottle is necessary. Most collectors use a cyanide bottle, in
which the fumes of cyanide of potassium kill the insects. One of the
best ways to make this is to place in a wide-mouthed bottle two or
three lumps of cyanide of potassium, approximately an inch across.
Over this place some fine sawdust and on top of the sawdust, pour
liquid plaster of paris carefully so that it will harden into a layer
about half an inch thick. Allow the plaster to become thoroughly dry,
then insert the stopper into the bottle and it will be ready for use.
It is better to use a ground glass stopper so that the bottle will
always be air tight. The sawdust is often omitted, the plaster of
paris being poured directly over the cyanide. The special advantage of
the sawdust is that it tends to absorb the cyanide in case it
liquefies, as it often does in damp weather. As this cyanide is a
deadly poison, it is better to let a druggist prepare the bottle or
else to buy it already prepared of the dealers in such supplies.
[Illustration: Butterfly Envelopes. Fold first on line _AB_;
then on _AD_ and _CB_; then on _BF_ and _EA_. (From Holland).]
After the specimens have been killed in the cyanide bottle, some
method of keeping them is necessary. The simplest way is to preserve
them with their wings closed together in pieces of paper folded over
into triangles as indicated on the accompanying diagrams. Such
specimens may be kept for an indefinite time and if one wishes to
mount them later, it is only necessary to place them for a few hours
in a relaxing jar, which is simply a closed vessel with enough water
in the bottom to saturate the air with moisture. A great advantage of
keeping the specimens in these paper covers is that they require so
little room and are easily stored away in tin cans or boxes where they
are safe from dust and destroying enemies.
[Illustration: Setting Board with Butterfly in place.
(From Holland)]
Those butterflies which are to be preserved in the ordinary way, in
drawers or cabinets, must be spread out and held in position while the
body is drying so that the wings will remain expanded. For this
purpose, some form of a setting board is necessary. These may be
bought of dealers or made at home. One of the simplest kinds consists
of two thin strips of pine board, a foot or more long, nailed to end
pieces with a space between the two boards wide enough to accommodate
the bodies of the butterflies. Beneath this open space, a piece of
thin cork is tacked. The pin on which the butterfly is fastened is
pushed through the cork until the wings of the insect are level with
the boards. The wings are then brought forward with a needle point
until they are in the desired position and they are then held in place
by pieces of glass or by bits of cardboard fastened down by pins. The
butterflies must be left in this position until thoroughly dry.
[Illustration: Drying Box for Setting Boards. (After Riley)]
Special insect pins should be used for butterflies. These are longer
than common pins and have rounded heads. They are offered for sale by
entomological dealers. Instead of pinning the insects and preserving
them in cabinets, one may keep them in the Riker mounts, which have
the advantage of being sealed so that there is no chance for dust or
museum pests to reach the specimens. If one wishes to collect
extensively, one will need a considerable number of setting boards and
it will be worth while to prepare for them a special drying box like
that shown in the picture above.
PART II
THE TRUE BUTTERFLIES
SUPERFAMILY _Papilionoidea_
The great suborder of butterflies is commonly separated into two
principal groups called superfamilies. One of these includes all of
the higher butterflies and is named _Papilionoidea_. The other
includes the lower Skipper butterflies and is named the
_Hesperioidea_. The former are characterized by small bodies and
relatively large wings, straight clubbed antennae, and the fact that
the caterpillars do not make cocoons when preparing for the chrysalis
state.
The most authoritative classifications of butterfly families are based
upon the peculiarities of wing venation and are admirably discussed in
such books as Holland's "Butterfly Book" and Comstock's "How to Know
the Butterflies." Without attempting to go into the technical details
of structure it will suffice here to give the list of families which
compose the superfamily _Papilionoidea_:
The Parnassians. _Parnassiidae._
The Swallowtails. _Papilionidae._
The Whites, Orange-tips, and Yellows. _Pieridae._
The Nymphs. _Nymphalidae._
The Satyrs or Meadow-browns. _Agapetidae._
The Heliconians. _Heliconidae._
The Milkweed Butterflies. _Lymnadidae._
The Long-beaks. _Libytheidae._
The Metal-marks. _Riodinidae._
The Gossamer-wings. _Lycaenidae._
It must not be thought that such a list necessarily indicates the
degrees of development of the respective families, for this is not
true. It is simply a linear arrangement adopted for convenience by
leading authorities, notably Dr. Harrison G. Dyar in his standard
"Catalog of American Lepidoptera."
THE PARNASSIAN BUTTERFLIES
FAMILY _Parnassiidae_
It is perhaps a bit unfortunate that the group of butterflies, which
is commonly chosen to head the list of families, is one that is rarely
seen by most collectors. The Parnassians are butterflies of the far
north or of high elevations in the mountains. The four species
credited to North America have been collected in Alaska and the higher
elevations of the Rocky Mountains, so there is very little probability
of any of them being found in the Eastern states.
While, structurally, these butterflies have a close affinity with the
Swallowtails, one would never suspect it from their general
appearance. Their bodies are large and all of the wings well rounded,
so that there is more of the suggestion of a large moth than of the
Swallowtail. The coloring is also more moth-like than with most
butterflies, the wings being very light colored and nearly
transparent, with markings of gray and brown, arranged in dots and
splashes.
All our species belong to the genus Parnassius. The caterpillars show
their affinity with those of the Swallowtails by having the curious
scent organs or osmateria just back of the head. They feed upon such
alpine plants as stonecrop and saxifrage and are well adapted by their
structure and habits to the bleak surroundings of the mountain tops.
As a typical example of the environment in which these butterflies
live, we may take the alpine valleys of such mountain regions as
Pike's Peak. Prof. M. J. Elrod has described a visit where, at an
altitude of 11,500 feet in the month of August, _Parnassius smintheus_
was flying by thousands, and the earlier stages were so abundant that
a water ditch had the surface covered as far as one could see with the
dead or dying caterpillars. In such situations, where ice forms at
night, and snow frequently falls by day, these butterflies develop
apparently in greater numbers than almost any of our other species are
known to do in warmer regions.
THE SWALLOWTAILS
FAMILY _Papilionidae_
This is probably the most distinctive family of all our familiar
butterflies. Its members are characterized by being on the whole the
largest butterflies in our region and by having the hind wings
prolonged into curious tail-like projections, suggestive of those of a
swallow. In general, the basal color of the wings is blackish though
this is commonly marked in various striking ways with yellow, green,
or blue, while the margins of the wings are commonly adorned with red
or orange spots. These butterflies are also characterized by certain
peculiarities in the branching of the wing veins which will be found
pictured in more technical works.
The caterpillars of these butterflies have the characteristic form
pictured on the plate of the Swallowtails opposite page _80_. When
full grown they are large, fairly smooth-bodied worms, showing at most
on the surface sparse fine hairs or fleshy threadlike projections.
Their most characteristic feature is found in the scent organs called
_osmateria_ situated in the back just behind the head. These are
thrust out, generally, when the caterpillar is disturbed and appear as
orange Y- or V-shaped organs from which an offensive odor is commonly
given off. They are supposed to serve the purpose of preventing injury
by enemies, possibly birds, monkeys, and other vertebrates.
Structurally, they are like long tubular pockets that can be turned
inside out. When the pocket is in place it is getting a pocketful of
odors. When it is inverted it lets these odors free. On this account
Professor Comstock has aptly called these caterpillars "the polecats
of the insect world."
When ready to pupate, these Papilio caterpillars spin a web of silk
upon some more or less flattened surface and a loop of silk near by.
They entangle their hind legs in the former and keep their heads
through the latter so the loop supports the body a little behind the
head. Then they change to chrysalids which are held in place by these
sets of silken threads.
The chrysalids are rather large and angular and generally take on
colors approximating their surroundings. They vary so much in
different species that one familiar with them can recognize the
chrysalis and know the kind of butterfly it will produce.
=The Black Swallowtail=
_Papilio polyxenes_
While the Black Swallowtail is not so large as some other members of
the group, it is probably the best known to most people. It is found
throughout many months of the year in practically all parts of North
America south of Canada, and has the habit of flying freely about
fields and gardens in search of flowers from which to suck its nectar
food, and of plants on which to deposit its eggs. The female
butterflies have a remarkable ability in selecting only members of the
great family Umbelliferae for this purpose. In consequence the
caterpillars are generally to be found feeding upon carrots, parsnips,
parsley, and various wild species belonging to this order. (_See
plates, pages 48 and 64-65._)
The eggs of the Black Swallowtail are laid one in a place upon the
leaves of the food plant. Each egg is a small, yellowish, smooth, and
ovoid object. It may often be found by watching the butterflies as
they fly low in search of umbelliferous plants, and seeing one stop
for a minute or so while she lays the egg.
About ten days after the egg is laid it hatches into a small black
caterpillar marked in a characteristic fashion with a blotch of white
in the middle of the body which is suggestive of a saddle. The
caterpillar immediately begins to feed upon the green substance of the
leaf, continuing thus about a week before the first moult. At this
time it does not change much in appearance, still being a spiny
creature blackish in color and marked by the curious white saddle. A
little later it moults again, retaining its original coloring. At each
moult, of course, it gets larger and feeds more freely upon the celery
or other plant on which it may happen to be.
When the caterpillar becomes about half grown it takes on a very
different appearance from that of its early life. The skin is smooth
rather than spiny, and the general colors are green, black, and
yellow. The ground color of the skin is green, which is marked with
black cross-bands along the middle of each body ring. On these bands
there are many large dots of orange yellow, the whole coloring giving
the insect a very striking appearance, especially when it is placed by
itself against a plain background. When they finally become full grown
in this larva state, these caterpillars are almost two inches long.
The larvae of the Black Swallowtail have certain characteristics in
which they differ from many other caterpillars. After each moult they
do not devour their cast skins, which happens in the case of many of
their relatives. When feeding, as well as when resting, they remain
exposed upon the leaf and seem never to attempt to conceal themselves,
as is the habit with a large proportion of caterpillars. It is
probable that this instinct for remaining exposed to view bears some
relation to the curious means of protection possessed by this as well
as other Swallowtail caterpillars. When disturbed one of these larvae
will push out from just back of the head the strange-looking,
orange-yellow Y-shaped organ which gives off a very disagreeable odor.
These osmateria organs are generally believed to be defensive against
the attack of birds and various other enemies, although they seem not
to be effective against insect parasites.
The full-grown caterpillars are likely to leave their food plants when
ready to change to the chrysalis state. They wander in various
directions until suitable shelter is found. A piece of board, a fence
post, or possibly the bark of a tree will answer for this purpose.
Here the caterpillar spins a mat of silk in which to entangle its hind
legs and a short distance away near the front end of the body it spins
a loop of silk attaching the ends to the support. These serve to hold
the chrysalis in place during this helpless period. After the loop is
made the caterpillar keeps its head through it so that the loop holds
the insect in position a short distance back of the head. It is now
ready to moult its last caterpillar skin and become a chrysalis.
One who has watched hundreds of these caterpillars go through this
change, Miss Mary C. Dickerson, describes the process in these words:
"In this final moult the chrysalis has to work very hard. The bulk of
the body is again slipped forward in the loosened caterpillar skin, so
that this becomes tensely stretched over the anterior end, and very
much wrinkled at the posterior end. The skin splits back of the head
and is forced back by its own taut condition and by the efforts of the
chrysalis, until only the extreme posterior end of the chrysalis is
within it. Then the chrysalis withdraws this posterior end with its
many very tiny hooks, from the skin on the dorsal side, and, reaching
around, securely fastens the hooks into the button of silk. Then the
old skin is removed both from its fastening to the chrysalis and from
its attachment in the button of silk."
A short time after the caterpillar's skin has thus been cast off the
chrysalis takes on a brownish color which as is so often the case is
likely to vary somewhat according to the tint of the surrounding
surfaces. This is doubtless a protective device and helps the insect
to escape attack by birds during the long period of exposure. For this
butterfly passes through the winter only in the chrysalis condition,
and the larva which went into the chrysalis in September does not come
out as a butterfly until the following May or June. There are,
however, two broods of the butterflies in the North and at least three
in the South. As the adults live for about two months and there is
considerable variation in the periods of their development it happens
that one can find these Black Swallowtail butterflies upon the wing
almost any time in warm weather, either North or South.
=The Giant Swallowtail=
_Papilio thoas_
The largest of our North American butterflies is a magnificent insect
with a wing expanse of some four inches and with a rich coloring of
black and yellow more or less suffused with greenish or bluish
iridescence that gives it a striking beauty as it flies leisurely
about from flower to flower or stops to lay an egg upon some bush or
tree. The tails are long and expanded toward the tip, their prevailing
color being black with a broad splash of yellow near the end. In a
general way we may say that the upper wing surface is black marked
with two bands of orange-yellow, while the under surface is yellow
marked with two bands of black. (_See plate, page 64._)
The Giant Swallowtail is a tropical species which is abundant
throughout the Southern states and during recent years seems to have
been gradually extending its northern range. It is now commonly found
as far north as forty-two degrees latitude, from Nebraska eastward. In
New England it is occasionally taken in Connecticut, Massachusetts,
and even in Maine, but its appearance in this region is exceptional.
In the orange-growing regions of the Southern states the caterpillars
of this butterfly feed freely upon the leaves of citrus fruits and
they are often called "orange puppies" or "orange dogs." Probably
their curious appearance and their habit of resting for long periods
upon leaf or twig gave rise to this name. In the region indicated the
life-history of the insect may be summarized thus:
The mother butterfly deposits the eggs singly upon the young growth of
orange or other citrus fruit trees, generally near the tips of leaves
or branches. About a week later each egg hatches into a caterpillar
that feeds upon the young leaves, resting upon the lower surface when
not eating. After a few days of this feeding the caterpillar becomes
too large for the skin with which it was born and it moults, coming
forth with a new skin which soon hardens so that it can begin feeding
again. A week or so later it moults for the second time, and continues
these processes of feeding and moulting until full grown, which is
perhaps a month from the time of hatching from the egg. At first the
caterpillars eat only the succulent young leaves and branches, but as
they grow larger they feed more freely upon the older foliage. They
are very voracious and when abundant may often do much damage
especially to young trees. When ready to change to the chrysalis each
caterpillar attaches itself by silken threads to the bark of the
trunk or branch of the tree. Here it changes to a chrysalis which
takes on a color so similar to that of the bark that the insect is
surprisingly difficult to discover. A fortnight or so later it changes
again into a fully developed butterfly that sallies forth in search of
the nectar of flowers. (_See plate, page 240._)
These "orange dogs," like the caterpillars of other Swallowtail
butterflies, have curious yellow scent organs which, when the
caterpillar is disturbed, protrude from the upper surface just behind
the head. These give forth a very disagreeable odor which is believed
to serve the purpose of repelling birds and possibly other enemies. It
has been noticed that these caterpillars are not molested by birds
although they are attacked by various insect enemies. Each mother
butterfly is known to be able to deposit four or five hundred eggs and
it has been suggested that the injuries of the caterpillars may be
checked by shooting the butterfly upon the wing with cartridges loaded
with small bird shot. In the South there are several broods in a
season.
The life-history of this species in more northern regions differs in
the choice of the food plant and the number of broods. It feeds upon
various members of the rue family, including common rue and prickly
ash, as well as upon certain poplars and probably other trees. It is
two brooded and apparently winters as a chrysalis. The butterflies of
the first brood come from the chrysalis about the last of May and are
found on the wing during June. Those of the second brood come from the
chrysalis about the last of July and are found on the wing during
August and September. The length of time required from the laying of
the egg to the emergence of the butterfly varies greatly with the
locality and the temperature. It commonly extends over a period of
four or five weeks.
[Illustration: _From a drawing by Mary E. Walker_ _See page 62_
GIANT SWALLOWTAILS
Visiting blossoming branches of the orange tree. (Reduced)]
[Illustration: _See page 59_
BLACK SWALLOWTAIL VISITING THISTLE, SHOWING THE TONGUE
PARTIALLY UNCOILED]
[Illustration: _Photographed from life_ _See page 83_
IMPORTED CABBAGE BUTTERFLY
(A good deal magnified)]
[Illustration: _See page 65_
THE BLUE SWALLOWTAIL
Upper surface above; lower surface below]
=The Blue Swallowtail=
_Laertias philenor_
The Blue Swallowtail is said to have closer affinity with the splendid
butterflies of the tropics than most of our other Papilios. The sheen
of metallic color upon its wings is certainly suggestive of the broad
expanse of similar colorings in the gorgeous butterflies from South
America. This species is easily recognized by the general blackness of
the front wings and the basal parts of the hind ones as seen from
above, about two thirds of the area of the latter being overlaid with
blue-green scales that give the metallic lustre characteristic of the
species. Near the outer border of the basal half of the front wings
there is a row of about five rather indistinct whitish spots, this row
being continued more distinctly on the hind wings. On the under
surface the white spots of the front wings are more pronounced than on
the upper, while each hind wing is brilliantly marked with about seven
large orange spots, part of them fringed on one or both sides with a
distinct margin of white. The extreme side borders of all four wings
are distinctly marked with white crescents and the fringes on the
tails as well as more or less of the darker fringes of the hind wings
are of a beautiful purple color. In the males each hind wing has along
the inner border a slender, pocket-like depression which is said to be
the seat of the scent organs. (_See plate, page 65._)
This splendid butterfly is a southern species. It is found from the
Carolinas to California, being at times extremely abundant in certain
localities over this great region. It seldom occurs as far north as
New England and in a general way east of the Rocky Mountains its
northern limit approximates that of forty-three degrees of latitude.
It varies considerably in size and differs greatly in abundance in
different localities and different seasons.
[Illustration: Caterpillar of the Blue Swallowtail.
(After Riley)]
Probably the commonest food plant of the caterpillars is the
Dutchman's Pipe or Aristolochia, which is frequently planted as an
ornamental vine for porch adornment. It also feeds upon wild ginger or
Asarum and probably upon other plants. A dozen or more eggs are laid
upon a leaf by the mother butterfly, usually in a cluster or grouped
near together. They hatch a week or so later into small brownish
caterpillars which remain together for awhile in little groups that
feed side by side upon the leaf, beginning at the margin and working
toward the centre. As they become larger they feed more freely and
gradually disperse so that each forages for himself. As they approach
maturity their appetites become voracious and their presence is often
shown by the defoliated condition of the branches. They have back of
the head the osmateria or scent organs which are commonly found in
the other caterpillars of this genus, but the odor emitted by them is
likely to be less pronounced than usual.
[Illustration: TWO OF THE SWALLOWTAILS
(Three fourths natural size)
The Palamedes (_see page 76_)
The Giant (_see page 62_)]
[Illustration: _See page 67_
THE GREEN-CLOUDED SWALLOWTAIL
Upper surface above; lower surface below]
When full grown the caterpillars find such shelter as they may and
each spins a bit of silken web and a silken loop which hold it while
it changes to the chrysalis. This chrysalis is very likely to take on
the colors of the immediate surroundings and thus be rather difficult
to see. If the egg was laid by one of the spring or early summer
butterflies, the chrysalis will soon change to a butterfly which will
appear toward midsummer and which may lay eggs for another brood of
caterpillars. These caterpillars mature to chrysalids the same season
and some of them are believed to change into butterflies in autumn,
these butterflies hibernating through the winter; while others are
believed to remain unchanged through the winter and disclose the
butterfly the following spring. This is an exceptional condition for
the Swallowtails and it is worth while to make careful observations
along its northern limits to learn more definitely the facts as to the
winter condition.
=The Green-clouded Swallowtail=
_Papilio troilus_
This beautiful butterfly is essentially a southern species and is
found over a wide range of territory from the Mississippi River to the
Atlantic Ocean. It occurs as far north as New Hampshire and Vermont
and has even been reported from Alberta, Canada. It is easily
recognized by the blue-green clouding of the upper surface of the
wings, the general color being velvety black with distinctive rows of
yellow spots along the margins of the front wing. These spots are
present also on the hind wing where they are almost changed to blue
because overlaid with a general cloudiness of this color. On the under
surface of the hind wings there are two rows of orange-brown spots,
the inner row being nearly crescent-shaped and the outer row oblong.
In the living insect the tail projections on the hind wings are
usually twisted into a vertical plane at right angles to the plane of
the wings.
The caterpillars of this species feed upon the leaves of sassafras and
spice bush. The distribution of the butterfly appears to be closely
related to the distribution of these plants.
As is the case with so many of our Swallowtail butterflies, the
Green-clouded Swallowtail passes through the winter in the chrysalis
stage. Late in spring the butterflies emerge and soon afterward lay
their eggs singly upon the leaves of sassafras or spice bush. The eggs
soon hatch into lead-colored caterpillars, largely covered with spiny
warts. Each caterpillar cleverly makes a protecting nest by eating out
a narrow strip in the leaf which frees a flap along the margin that is
turned back upon the leaf, making a case in which the larva lives. It
spins a silken carpet on one side of the case and rests upon this
carpet when at home. During its feeding periods it goes outside and
eats the tissues of the other parts of the same leaf. It continues to
occupy this first nest for a week or more by which time the rest of
the leaf is likely to be pretty well consumed.
Having passed the first moult and thus become larger and having
practically eaten itself out of its first house and home the
caterpillar now crawls to a larger leaf where it proceeds to make a
more enduring structure. In this case it does not need to bite a
channel along one side of the midrib as it did before, but instead it
begins to spin silken threads transversely across the upper surface in
such a way as to fold over the border of the leaf and make a tubular
chamber in which it has plenty of room to move about. It uses this as
its home for some time thereafter, wandering out at evening to feed
upon neighboring leaves as its hunger necessitates. In this way it
continues to feed and grow for a week or two. Then it finds it
necessary to construct still another home, which it does by bringing
together the opposite sides of a leaf, taking care to have a door-like
opening at the base of the blade next the leaf stalk. This third home
serves it to the end of its larval existence. It goes in and out as
necessary, remaining concealed when it casts its skin and until the
body tissues harden afterward. Apparently it devours the cast skin and
thrusts the hard covering of the head out of the nest. Consequently
these little homes are clean and sanitary and serve admirably their
protecting purpose.
The full-grown caterpillars have the curious appearance of those of
the other Swallowtails. The third ring behind the head is greatly
swollen, making, with the rings directly in front of it, a
characteristic picture suggesting a grotesque face with large eye-like
spots at the top. The general color is green, darker above than below,
and there are six rows of blue dots along the body. (_See plate,
page 80._)
When ready to change to the chrysalis, the caterpillars desert their
leafy homes and on a twig or board or stone each spins a bit of silken
webbing and a silken loop. They now change to chrysalids which are
likely to resemble the color of the background and which are somewhat
smoother than many of the Swallowtail chrysalids. About two weeks
later the butterflies emerge.
_The Eclosion of the Butterfly_
The transformation of a chrysalis into a butterfly is always one of
extraordinary interest. Comparatively few definite descriptions of
this process have been given by careful observers. One of the best of
these is that written by Mr. Scudder in connection with the emergence
of this butterfly, and it is so accurate and complete that it seems
worth while to quote it at length:
"The butterfly generally emerges from the chrysalis early in the day,"
writes Mr. Scudder, "and the first signs of the immediate change are
strong forward and backward movements of the chrysalis at intervals of
a few seconds; perhaps the third or fourth attempt will be successful,
when a click may be heard at the distance of several feet; but all the
subsequent movements are absolutely noiseless, though rapid; at
intervals of three or four seconds, spasmodic movements similar to the
first carry on the process; first the split continues along the
thorax; then it runs down either side between the legs and wings,
ultimately to the tips of the antennae. As this progresses, the
actions become more strenuous and more frequently repeated; with eager
efforts the butterfly pushes forward its half-detached head; now an
antenna springs from its case, at once assuming its natural attitude;
the other soon follows, and then the wings are partially drawn from
their sheaths, and while in this position seem to be used as levers or
arms to aid in withdrawing the rest of the body; next the legs appear,
seize the upper part of the chrysalis skin, and speedily withdraw the
whole body. It is now a curious-looking object, the wings wrinkled
and bloated, and, although the whole process of escape lasts little
more than half a minute, already twice the size of the sheaths they
lately occupied. The insect crawls upward until it finds a secure
resting place, and there remains until ready for flight; each half of
the tongue, drawn independently from its receptacle, is rolled in a
separate spiral, and now while the wings are gradually expanding the
insect applies all its energies to uniting their two parts,
incessantly rolls and unrolls them, and beginning simultaneously at
the base, gradually fits them together by their interlocking joints;
in about fifteen minutes all but the tips are perfectly united; these
require nearly fifteen minutes more, and are not fairly interlocked
until the wings are fully expanded, nearly a full half hour after the
escape from the chrysalis; the wings, however, are still tender, and
generally require two hours to stiffen. When at last the insect
ventures upon flight, it is not with an uncertain flutter, but boldly
and steadily, as if long accustomed to the action."
The butterflies of this second brood of the season are likely to begin
to appear early in August, continuing to become more abundant
throughout that month. These lay eggs upon the same food plant and the
caterpillars grow to maturity in the same way as those of the first
brood. They become full grown during September or October, and then
change to chrysalids which remain dormant until the following spring.
The species thus has two broods each year and passes the winter only
in the chrysalis state.
These beautiful butterflies are likely to be found in the sort of
situations where the food plants of the larvae are growing. Open
groves, the borders of woods, and the margins of streams or marshes
are the places where one is most likely to find spice bush and
sassafras. These are the places to look for these butterflies which
one may often see in graceful flight near the ground, pausing now and
then to seek a sassafras leaf or to sip the nectar from a flower.
=The Tiger Swallowtail=
_Papilio glaucus_
One of the many things that make a study of the life-histories of
butterflies of great interest is the variations in the development of
many of the species. One who follows the simplest life-story of a
butterfly and sees the egg change to larva and the larva change in
size and form and color with each successive moult and then change
again into the seemingly inert chrysalis, from which there finally
comes the winged butterfly--unlike the egg, unlike the larva, unlike
the chrysalis--a creature of perfect beauty, wonderfully adapted to
living freely in the air and sipping ambrosial nectar from the
flowers--one who follows these changes with awakened vision can
scarcely fail to have a sense of wonder as to the laws that govern
such intricate phenomena. But the marvel is still more pronounced in
the case of those butterflies which have two or more forms arising
from the same lot of eggs in a way which science has as yet not
adequately explained.
The splendid Tiger Swallowtail is an example of this dimorphism which
is of especial interest because of the fact that the extra form is
confined to one sex and to only a part of the geographical area over
which the butterfly is found. The species occurs over a very large
part of the North American continent, being found from ocean to ocean
and from Canada to Florida. In the region north of approximately the
fortieth degree of latitude there is but one form of the insect--the
familiar yellow-and-black striped butterfly which every one has seen
visiting the lilac blossoms in May or June. South of this, however,
part of the females take on an entirely different appearance, being
almost wholly black with the hind wings touched with lines of blue and
bordered with crescents of yellow and orange. The curious thing about
it is that a certain mother butterfly may lay a dozen eggs part of
which will develop into the usual yellow form and the rest into the
black form, both lots being of the same sex. This black form is so
entirely distinct in appearance that the two were originally described
as separate species, and they were long considered such, until
breeding experiments determined the precise condition. (_See plate,
page 17._)
This species is of interest also for another reason. The caterpillars
during their later life are remarkable examples of that curious
resemblance to the head of a serpent which is thought to have a real
protective value in frightening away attacking birds and possibly
other enemies. The rings of the body just back of the head are much
swollen and on the top of the swollen part there are two large
circular marks which bear a striking resemblance to eyes. When the
insect is at rest it withdraws its head and holds up the front of the
body in such a way as certainly to suggest at the first glance that
one is looking at the head of a small snake, an impression which is
likely to be enhanced when the caterpillar pushes out the curious
yellow scent organs from the ring near the top of the head, these
organs taking on the forked appearance of a snake's tongue.
Obviously it is exceedingly difficult to get definite observations
under natural conditions to determine whether these seeming
resemblances are really of value to the caterpillar in frightening
away birds or other enemies. About the only direct evidence which I
have come across upon this point is found in this paragraph by Dr. J.
L. Hancock:
"When I recall the first sight of this larva, the impression gained of
it was a most curious one. The forward mask-like face was remarkably
startling. This mask, bearing eye-like spots and the light transverse
ridge, gave it an aspect which might easily be mistaken for real eyes
and a mouth. This contrivance is only a false face in no way connected
with the real eyes and mouth. One might imagine the shock that a bird,
or other predaceous enemy, would experience when looking upon this
grinning mask. This is in reality the effect produced, for I have seen
small birds so alarmed that they lost their appetite and curiosity for
these larvae after a brief glance at them. It is certain that these
singular markings have the effect of terrifying their bird
enemies."[B]
[B] "Nature Sketches in Temperate America," p. 146.
The yearly cycle of the Tiger Swallowtail is much like that of the
related species. It passes the winter as a chrysalis, the butterflies
coming forth just about the time that the lilacs bloom. They remain
upon the wing for a few weeks and deposit their eggs upon a great
variety of trees and shrubs, for the food plants of the larvae are
unusually varied and include tulip trees, birches, wild cherries,
apples, poplars, ash, and several other common trees or shrubs. These
eggs soon hatch into caterpillars that feed upon the leaves and make
for themselves resting places by spinning a web of silk transversely
across the surface of the leaf. They remain upon these silken webs
when not feeding and in later life are likely to cause the leaf on
which the web is made to curl into a partial tube. When fully
developed they change to chrysalids which give forth the summer brood
of butterflies in July and August. These in turn lay eggs for the
caterpillars which change to chrysalids in autumn and remain in that
condition until the following spring.
=The Short-tailed Papilio=
_Papilio brevicauda_
Were one enough of a magician to make one butterfly over into another
it would be comparatively easy to take a Black Swallowtail and
transform it into this species. One would only need to trim off the
long tails so that they project very slightly from the angles of the
hind wings and to change the yellow spots to orange. He would thus
accomplish what Nature through the long ages seems to have
accomplished in a limited northern area in Newfoundland and around the
Gulf of St. Lawrence, for the Short-tailed Papilio is confined chiefly
to this region, where it lives a life very similar to that of the
Black Swallowtail. The caterpillar feeds upon the leaves of various
members of the parsley family and is said to have learned to warm
itself during the middle of the day by resting upon stones and gravel
which have absorbed the sun's heat rays. Presumably there is but one
brood a year and the insect hibernates as a chrysalis.
=The Palamedes Swallowtail=
_Papilio palamedes_
If the magician who had succeeded in converting a Black Swallowtail
into the Short-tailed Papilio wished to try his hand on making a
Palamedes Swallowtail he could not do better than to use again the
same black butterfly. He would only need to make it about one half
larger, retaining practically all its color markings and the outline
of its wings and tail. For this species bears a remarkable resemblance
to the Black Swallowtail, seeming to be a giant variety induced by the
warmth of the southern climate where it lives, and possibly by the
more generous supply of the magnolia and sassafras leaves upon which
the caterpillars feed.
This species is distinctly a southern form occurring as far west as
the Mississippi River throughout the more Southern states. As one
would expect in the long seasons and warm climate of this region there
are several broods each year and the caterpillars often hibernate as
well as the chrysalids. The adult butterflies are lovers of the sun
and are said to roost at night upon the tops of live oak and palmetto
trees.
=The Zebra Swallowtail=
_Iphiclides ajax_
Most of our Swallowtail butterflies are so distinctive in form and
colors that they are easily distinguished from one another, but the
Zebra species is so different from all the rest that when it is once
seen it is likely always to be remembered. The striking combination of
green and black stripes with very long tails, set off by beautiful
crescents of blue and of red, at once distinguishes this fine
butterfly in any of its varying forms.
Three distinct forms of this species occur, namely:
_Marcellus_, the early spring form, small in size with short tails,
that show white only on the tips;
_Telamonides_, the late spring form, somewhat larger, with tails a
little longer and showing more white on the outer half;
_Ajax_, the summer form, decidedly larger with tails very long.
It would be a comparatively simple matter to understand these forms if
they were simply seasonal variations, with three broods, each form
succeeding the other as the season advances. But this is far from
being the case. We have instead the most complicated and confusing
series of conditions imaginable--conditions for which no one has yet
given satisfactory explanations.
To make a fairly clear statement of what happens, suppose we assume
that we start with twenty over-wintering chrysalids. In April ten of
these disclose their butterflies which are Marcellus, the early spring
form. In May the other ten disclose their butterflies which are
Telamonides, the late spring form. We thus have these two forms,
appearing successively in spring from the same set of over-wintering
chrysalids.
After flying about for a short time the Marcellus or early spring
Swallowtails lay eggs upon the leaves of papaw trees or bushes. These
eggs soon hatch into caterpillars that feed upon the leaves and grow
rather rapidly. A little more than a month later they mature into
butterflies which are Ajax, the summer form.
In a similar way the Telamonides or late spring butterflies lay eggs
soon after they appear, also upon papaw leaves, and these eggs in
about a month mature into Ajax, the summer form.
So we have Ajax, the summer form, developing directly from both the
early spring or Marcellus and the late spring or Telamonides
butterflies.
These Ajax butterflies in their turn lay eggs for caterpillar young.
These soon mature into a brood of butterflies which are of this same
Ajax form. There may be successive broods through the summer,
practically all of them being this same Ajax summer form.
The last brood of caterpillars, however, change to chrysalids which do
not disclose the butterflies until the following spring. And then the
first that come out are the Marcellus form and the last the
Telamonides form. So we may have these two forms maturing from the
same brood of autumn caterpillars.
This seems a sufficiently complicated life-history to suit the most
persistent solver of puzzle problems, but there is an additional
factor which adds much to the possible confusion of the broods. In
each brood of caterpillars from the earliest to the latest there are a
certain number of chrysalids which remain dormant through the
remainder of the season and the following winter, maturing into
butterflies the next spring. Consequently at the end of every winter
there are a miscellaneous lot of chrysalids which represent every
brood of caterpillars that lived the previous season, and all of these
develop into either Marcellus or Telamonides butterflies.
Such a condition of affairs certainly represents what an old New
Englander would be likely to call a "mixed-up mess," and it is
difficult for science to find rhyme or reason to explain it. It speaks
eloquently for the perseverance of W. H. Edwards that he was able with
infinite patience through years of study and experiment to untangle
this intricate web of butterfly existence.
While the preferred food plant of this species is papaw, the
caterpillars are also known to feed upon the spice bush and upland
huckleberry. When full grown these caterpillars are about two inches
long and of a general pea-green color, banded transversely with yellow
and black, and having an especially conspicuous band of this sort on
the third ring behind the head. The scent organs are protruded when
the larva is disturbed and emit an offensive odor. The chrysalids are
green or brown according to the surroundings.
The Zebra Swallowtail is a southern butterfly found as far west as
Texas and the Rocky Mountains and having its northern limits in a zone
ranging approximately from Massachusetts to Nebraska. It is especially
abundant in the Southern states east of the Mississippi River.
Mr. S. F. Denton found this species abundant in southern Ohio where
the females laid their eggs upon the small papaw bushes. They selected
the leaves of these bushes for sleeping quarters, "clinging to the
under side of the leaves where early in the morning they might be
taken with the fingers."
_Other Swallowtails_
Several other Swallowtail butterflies are found within the limits of
the United States, especially in the Far West and along the southern
boundaries. Some of these occasionally migrate east or north so that
they are collected in the Central states. Thus _Papilio daunus_, _P.
oregonia_, and _P. zolicoan_ are all found in the "List of Nebraska
Butterflies," published by Mr. H. G. Barber, and the same species have
been taken in other states in or near the Mississippi Valley. These
and various others are described and pictured in Dr. Holland's
excellent "Butterfly Book."
_Synopsis of the Swallowtails_
_Tiger Swallowtail_: _Yellow form_ (_Papilio glaucus turnus_). Expanse
3 1/2 to 5 inches. Upper surface of wings bright yellow with each
black margin marked with a row of yellow spots. Both sexes throughout
its range. _Black form_ (_Papilio glaucus glaucus_). Black all over
with blue markings on outer half of hind wings and row of straw-yellow
crescents on borders of same. Females only, and only south of about
latitude 40 degrees.
_Giant Swallowtail_ (_Papilio thoas_ or _Papilio cresphontes_).
Expanse 4 to 5 1/2 inches. Upper surface black with two bands of
yellow starting at the inner margin of the hind wings and coming
together as a row of yellow spots at the outer angles of each front
wing. A yellow spot on each black tail. Under surface yellow.
_Zebra Swallowtail_. Expanse 3 to 3 1/2 inches. Easily known by the
stripes of green upon black and the long, slender tails. The different
forms vary in size and in the length of the tails. Scientific names
are: Early Spring Form, _Iphiclides ajax marcellus_; Late Spring Form,
_I. ajax telamonides_; Summer Form, _I. ajax ajax_.
[Illustration: _From a photograph from life by A. H. Verrill_
_See pages 7, 67_
CATERPILLARS OF THE GREEN-CLOUDED SWALLOWTAIL
In various stages of growth]
[Illustration: _Photographed from life_ _See page 83_
IMPORTED CABBAGE BUTTERFLY]
[Illustration: _Photographed from life_ _See page 215_
BLUE-EYED GRAYLING VISITING JOE PYE WEED
(Magnified)]
_Green-clouded Swallowtail_ (_Papilio troilus_). Expanse 3 1/2 to 4
inches. Black with about seven yellowish spots on outer margin of each
front wing and eight marginal spots on each hind wing, those at the
ends of row orange, the rest yellowish or bluish. Outer half of hind
wings clouded with greenish blue. Under surface black with two
distinct rows of yellowish spots on front wings and two rows of orange
spots on hind wings.
_Blue Swallowtail_ (_Laertias philenor_, often called _Papilio
philenor_). Expanse about 4 inches. Black or brownish black with most
of hind wings showing a bluish green iridescence. A row of marginal
spots on each hind wing, more or less distinct on the front wings.
Outer fringe with broad white markings interrupted by black ones.
Under surface of each hind wing with seven large orange spots, some
with partial borders of white.
_Black Swallowtail_ (_Papilio polyxenes_ or _Papilio asterias_).
Expanse about 3 inches. Black with two conspicuous rows of yellow
spots on outer half of wings, more distinct in males. On hind wings
rows of blue spots or splashes between the yellow ones. Orange-red
circle with black centre at inner angle of each hind wing. Under
surface with markings more distinct and more orange-yellow.
_Short-tailed Swallowtail_ (_Papilio brevicauda_). Much like the Black
Swallowtail but generally smaller, with very short tails, and with the
yellow markings more or less changed to orange. Confined to the
limited region of Newfoundland and the lands bordering the Gulf of the
St. Lawrence.
_Palamedes Swallowtail_ (_Papilio palamedes_). Expanse 4 to 4 1/2
inches. Much like the Black Swallowtail but considerably larger. A
curved yellow line on the head back of each eye. Found only in the
South.
THE WHITES, ORANGE-TIPS, AND YELLOWS
FAMILY _Pieridae_
The most familiar and abundant American butterflies are classified
together under the family name _Pieridae_, or the Pierids. Three
groups or tribes of them are popularly known as the Whites, the
Orange-tips, and the Yellows. Our two commonest butterflies, the White
or Imported Cabbage Butterfly and the Sulphur Yellow Butterfly, are
typical representatives of this family. Most of the rest, like these,
are of moderate size with rounded wings which are more or less marked
with black. There are six well-developed legs and the caterpillars of
practically all the species are cylindrical greenish worms which under
a lens are seen to be covered with short hairs. When the caterpillars
are ready to change to chrysalids they spin a web of silk upon the
supporting surface and just back of it, a loop of silk that serves to
hold the chrysalis in place and keep it from swaying back and forth.
The chrysalids are characterized by having a pointed projection on the
front of the head, the rest of the body being more or less angular.
Notwithstanding their close general resemblance to their food plants,
the caterpillars of this family suffer from attack by various enemies.
Birds find many of them, not only eating them themselves but also
using them freely for feeding the nestlings. Parasitic insects also
take a heavy toll from these caterpillars. This attack of enemies is
doubtless a chief reason why many of the common species are not much
more destructive.
THE TRIBE OF THE WHITES
Three white butterflies of approximately the same size are found
widely distributed over the United States. The most abundant species
is the White or Imported Cabbage butterfly. The next in abundance is
probably the Checkered White, and the rarest in most localities is the
Gray-veined White which is a northern form.
=The White or Imported Cabbage Butterfly=
_Pieris rapae_
There is probably no butterfly which one can generally find so easily
in its early stages as the White or Imported Cabbage butterfly which
is found practically wherever cabbages are grown and is generally so
abundant that caterpillars and chrysalids are readily discovered. In
the Northern states the insect passes through the winter within the
chrysalis, coming forth rather early in spring as the familiar white
butterfly with black dots upon the wings and blackish front angles of
the fore wings. (_See plates, pages 64-65 and 81._)
The butterflies that thus appear in spring flit freely about over
fields, meadows, and gardens, sipping the nectar of various early
flowers through their long, coiled tongues and stopping occasionally
to alight upon the leaf of a cabbage or other plant of the mustard
family to deposit the small, pale yellow eggs which remain attached by
a sort of glue. The adult butterflies continue their leisurely life
for a fortnight or more, thus extending the laying of the eggs over a
considerable period.
About a week after being deposited the egg hatches into a tiny green
caterpillar that begins feeding upon the tender surface of the cabbage
leaf. It is commonly called the cabbage worm and it is doubtless the
most generally destructive insect affecting this crop. It continues to
feed for several days before the first moult, after which it becomes
decidedly larger and begins to eat again more voraciously than before.
It undergoes several successive moults during the next two or three
weeks before it becomes full grown as a caterpillar. Unlike most
butterfly larvae it has changed very little in its general appearance
during its growth. It is always of a pale green color, strikingly like
the glaucous green of the cabbage leaf, a fact which doubtless helps
to conceal it from the eager eyes of birds and other animals.
When the caterpillar is thus full fed it is likely to leave its food
plant and find shelter elsewhere. Sometimes it will stop on the lower
surface of the outer leaves, but more commonly it will find a piece of
board, an overhanging stone, a fence-post, or the side of a building,
where it will prepare for the change to the chrysalis. It will do this
by spinning a silken thread upon the surface in which to entangle its
hind legs and a loop of silk near by with which to hold its body. When
these preparations are completed the insect will cast its last
caterpillar skin, emerging as a grayish or brownish chrysalis, the
color usually varying with the color of the surrounding surface.
A week or more later the chrysalis skin bursts open and the white
butterfly emerges to expand and dry its wings before it flies away for
its leisurely life. There are two or more broods each season, the
number varying with the latitude. There is a decided variation in the
length of time required for the completion of the cycle from egg to
butterfly. In hot weather the insect may mature in about three weeks
while in cooler weather it may require as much as five weeks.
_Its Introduction and Dispersal_
While it is well known that a large proportion of our most destructive
insects have been imported from Europe, it is only in comparatively
few cases that man has been able to make careful records of the times
and places where the insects were introduced and to follow the spread
of the pest from these original centres. The Imported Cabbage
butterfly is one of the few species of which this is true. This insect
has been known for centuries in Europe, where it feeds freely upon the
leaves of cabbages and turnips. So far as known it was first
introduced into North America about 1860, when it appeared in Quebec.
Eight years later it was again introduced into the region of New York
City. From these two points the insect spread gradually in various
directions until in 1871 it covered the whole of New England and
various parts of New York and New Jersey. From then on it spread even
more rapidly and was evidently accidentally introduced into various
parts of the country which became new centres of distribution. Of
course it would be very easy for this to happen through the shipment
of cabbages from one part of the country to another. Within thirty
years of the time of its first introduction it had become a serious
pest over practically all the United States and Canada.
The introduction and spread of such a pest is of interest in itself,
but in this case there is to be noted the additional fact that the
presence of this foreigner has practically led to the extinction of
two native species of butterflies, both closely related to each other
and to the invader and both feeding upon the same plants. An almost
pure white butterfly--the Gray-veined White--was formerly exceedingly
abundant in many of the Northern states, while farther south there was
another species, the Checkered White, which was also abundant. Both of
these have now so completely disappeared that in some localities they
are almost never seen, while their imported relative has become
perhaps the most abundant of all American butterflies.
=The Gray-veined White=
_Pieris napi_
One would naturally suppose that when a butterfly was reduced to the
greatest possible simplicity in its coloring there would be little
chance for the development of geographical or seasonal varieties. But
he would only have to study a large collection of specimens of this
species, taken at different seasons and in different regions, to find
his supposition at fault. Here is a butterfly which is essentially a
slender black-bodied creature with four white wings scarcely touched
with color, and yet we are told that there are eleven varieties in the
United States so distinct that they have received scientific names,
not to mention various others which have been found in Europe. This
is indeed a remarkable showing and it is a striking illustration of
the infinite variations which Nature can produce with the most limited
materials.
To me the seasonal variations of a butterfly are always of greater
interest than those which are geographical. We know that in the case
of a great many animals, from insects to mammals, the different
conditions of climate and physical environment found in different
regions produce variations of many sorts. So it does not seem
especially strange that in Alaska there should be a different form of
a certain butterfly than is found in Virginia. But that in the same
locality there should be two or more forms of a butterfly existing
under identical conditions as to climate and environment is not so
easily explained. In the case of the Gray-veined White we collect in
early spring in New England, or other Northern states, a lot of
chrysalids. We keep them until the butterflies come forth and we find
even here two distinct forms, one smaller and more delicate than the
other, with both surfaces of the wings pure white: scientists call
this form, _virginiensis_; the other larger with the under surface of
the wings slightly tinted with yellow: scientists call this form
_oleracea_. The first named has but one brood a year while the second
lays eggs which develop into caterpillars that produce butterflies of
still a _third_ form, in which the upper surface of the wings is pure
white with a slightly greater expanse: scientists call this form
_cruciferarum_. These three varieties occur in Eastern regions and may
be found in the same localities, and differ considerably from various
geographical varieties found in the Far West.
The caterpillar of the Gray-veined White is a bit smaller than those
of the nearly related forms, and in color is green with no distinct
longitudinal markings, but with many fine dots of black over the
surface. The cylindrical body is covered with a fine down. When
feeding upon cabbage it is more likely to attack the outer than the
inner leaves, and so even when abundant it is less troublesome to
gardeners than the imported species. It is now, however, so rare that
it seems to feed chiefly upon wild cruciferous plants and is more
likely to be found along the borders of open woods than in gardens and
fields. The winter is passed in the chrysalis state.
=The Checkered White=
_Pontia protodice_
Some years ago the Checkered White was commonly called the Southern
Cabbage Butterfly but the general distribution of the imported species
has had the same effect upon its abundance in the South that it has
had upon the Gray-veined White in the North. Consequently, it is now
much less abundant than formerly, even in the Southern states where it
is most at home. There are two fairly distinct forms: the spring form
and the summer form. The latter is practically of the same size as the
Imported Cabbage Butterfly: the males have the hind wings nearly white
above and the fore wings with a few black dots or spots upon their
outer halves. The females are much more definitely marked, having the
upper surface of both pairs of wings marked in black or brownish black
in such a way as to enclose a large number of white diamonds. The
spring form is decidedly smaller and the markings are much less
distinct than in the summer form.
The seasonal history of this species is comparatively simple. In
winter the chrysalids are found. From these chrysalids in early spring
the small butterflies of the spring form come forth. These lay eggs
upon various cruciferous plants which hatch into greenish caterpillars
that eat the leaves and soon mature so far as their caterpillar stage
is concerned. They are then about an inch long, with downy cylindric
bodies more or less marked with rather pale yellow stripes, touched
here and there with purplish green or dotted slightly with fine black
dots. These caterpillars now attach themselves by means of a button of
silk and a silken loop to some support like a piece of board, the side
of a stone, or almost any available shelter. Each casts its larval
skin and appears as a grayish chrysalis from which probably a
fortnight later the summer form of the butterfly emerges. There are
commonly two broods of this summer form, making three sets of
butterflies for the entire season. The caterpillars of the second
summer brood of butterflies go into the chrysalis stage in autumn to
remain throughout the winter.
Some very interesting observations upon the sleeping habits of this
butterfly have been made in St. Louis by Mr. and Mrs. Phil Rau. The
insects were found abundantly resting upon the seed heads of white
snakeroot. Early in October, when a warm south wind was blowing, the
great majority of the butterflies slept horizontally with their heads
toward the wind. At other seasons and in other places, many of them
were found in a vertical position but practically all had their bodies
toward the wind prevailing at the time. The observers were unable to
ascertain definitely whether the insects thus oriented themselves at
the time of alighting, so that their wings presented the least
resistance to the force of the wind, or whether this was a mechanical
result of the breezes.
=The Great Southern White=
_Pontia monuste_
There used to be in the Northern states before the advent of the
Imported Cabbage butterfly a familiar white butterfly which then laid
its eggs upon cabbages in much the same way that the imported pest now
does. One who has seen this northern Gray-veined White and then sees
the Great Southern White will be likely to think of the latter as a
larger edition of the former, for in the males of the southern species
the wings are practically white save for a narrow dusky border at the
outer angle of the front pair, although in the female this dusky
margin is wider and the hind wings show a series of dusky triangles
near the margin. There is also a curious black marking suggestive of a
crescent on each front wing near the middle of the front border, which
helps to make the appearance of this butterfly very distinct from that
of any other.
Although this species is at times so abundant that it swarms in great
flocks and although it has been known for many years, its life-history
seems not to have been carefully worked out since it was first
described by Abbott more than a century ago. The caterpillars feed
upon cruciferous plants and when full grown are about an inch and a
half long, of a general yellow color, more or less striped with
purple lines. The species is distinctly tropical extending northward
into our Southern states.
Dr. G. B. Longstaff reports this species as abundant in Jamaica where
he found that the clubs of the antennae of the living insects showed a
beautiful turquoise blue color, although another observer described
them as bright green with a tinge of blue. This is an interesting
color variation for a member of this group. In the tropics also there
are two forms, one belonging to the dry season and one to the wet
season.
_Synopsis of the Whites_
_Imported Cabbage Butterfly_ (_Pieris rapae_). Expanse 2 inches. Upper
surface white with a black marginal dash on the front outer angle of
the front wing. One round black spot on each of the four wings in the
male. Two round spots on each of the front wings in the female and one
round spot on each of the hind wings. Under surface of hind wings
yellowish white; spots on front wings in same position as on upper
surface. A spring form (_immaculata_) is smaller and the black spots
are almost obsolete.
_Gray-veined White_ (_Pieris napi_). Expanse 2 inches. Upper surface
white with only a darker marginal splash next the body. Under surface
white with gray veins.
_Checkered White_ (_Pontia protodice_ or _Pieris protodice_). Expanse
2 inches. Upper surface white, strongly marked especially in the
female with dark grayish brown on both pairs of wings. Along the outer
margins these marks are so arranged as to enclose white diamond spots.
Male with front wings only lightly marked and hind wings scarcely
marked at all. Under surface much like upper, with a slight yellowish
tinge in female.
_Great Southern White_ (_Pontia monuste_ or _Pieris phileta_.) Expanse
2 1/2 inches. General color white with a narrow black margin around
apical angle of front wings. These margins are wider in the female, in
which sex there is a series of marginal spots on the hind wings.
Easily known by its large size.
THE TRIBE OF THE ORANGE-TIPS
When one sees a gossamer-winged butterfly flitting from flower to
flower on a bright June day it seems one of the most ethereal of
earth's visions. One could readily fancy that the whole
sight--flowers, butterflies, and all--might easily vanish into thin
air. So it is something of a shock to hear scientists talk about
fossil butterflies and to realize that these fragile creatures have
been living generation after generation for untold millions of years.
A realization of this fact, however, helps us to understand the many
wonderful ways in which butterflies in all stages of their existence
have become adapted to the conditions of their lives.
There is perhaps no group of butterflies whose beauty seems more
fragile than that of the Orange-tips. These are delicate creatures,
with slender bodies and almost gauzy wings, of a size somewhat smaller
than our common white and yellow butterflies. Perhaps the most
remarkable feature is the marking of the wings, the upper sides of the
front pair having an orange patch near the apex and the under sides
having a background of delicate whitish or yellowish green, lined and
spotted with darker coloring in a very characteristic way. This
peculiar marking is so significant that it has been called "flower
picturing." To understand the reason for its existence one has only to
watch the butterflies in their native haunts. He will find them
flitting from blossom to blossom among the plants of the mustard
family--the _Cruciferae_. This is one of the most characteristic
families in the plant world: the foliage for the most part is small
and delicate and the flowers have a characteristic four-petaled
structure, being practically always of small size and generally toned
in whites or yellows. When an Orange-tip is at rest upon these
blossoms it merges so completely into the background that it
disappears from view. Should a bird chase one of these insects through
the air it would see chiefly the orange tips which are so marked upon
the upper side of the wing, and when the butterfly closed its wings
and lighted among the flowers the orange color would instantly
disappear and there would be only an almost invisible surface against
the background of flower and leaf.
The adaptations of these Orange-tips to the conditions of their lives
are by no means confined to this remarkable resemblance to the flowery
background. In the case of some species the whole yearly cycle has
been adapted to correspond to the yearly history of the cruciferous
food plant. As is well known many species of the mustard family spring
up early in the season, put forth their blossoms which quickly develop
into fruits and then die down, the species being carried through until
the next year by the dormant seeds. In a similar way the Orange-tips
feed as caterpillars upon the host plant through the spring,
completing their growth before the plant dies and then changing to
chrysalids which remain dormant through summer, fall, and winter and
come forth as butterflies early the following spring. The insect has
thus adapted itself in a most remarkable manner to the yearly history
of its plant host.
=The Falcate Orange-tip=
_Synchloe genutia_
The Falcate Orange-tip is about the only member of this tribe
generally distributed east of the Rocky Mountains. This is a beautiful
insect which is sparingly found even as far north as New England. It
is more abundant throughout the Southern states, occurring south at
least as far as Texas. It appears to be a good illustration of the
adaptation of its development to that of its food plants. The eggs are
laid upon leaves or stems of such spring-flowering _Cruciferae_ as
rock cress (_Arabis_), and hedge mustard (_Sisymbrium_). On hatching
the caterpillars feed upon stems, leaves, flowers, and even seed pods
of these plants, becoming mature in a few weeks and changing to
chrysalids under the protection of such shelter as they can find. In
the Northern states these chrysalids remain unchanged until the
following spring when the butterflies emerge and are found upon the
wing for a few weeks in May and early June. In some southern regions
at least the species is evidently double-brooded, as Dr. Holland
reports that he has taken the butterflies in late autumn in the
western portion of North Carolina.
[Illustration: Egg of _Synchloe genutia_, magnified 20
diameters. (From Holland)]
This Falcate Orange-tip is one of the daintiest and most exquisite of
northern butterflies. It is a prize which any collector will find joy
in possessing. It is easily recognized by its general white color,
which in the female is relieved only by a distinct black mark on the
upper surface of the front wings and a row of marginal markings upon
all the wings. The male is slightly smaller and is at once known by
the orange blotch on the outer angle of the upper surface of the front
wing. This outer angle projects into a distinct point which gives the
species its name Falcate. (_See plate, page 256._)
Dr. J. L. Hancock has described in a most interesting manner the way
in which this Orange-tip loses itself among the flowers of rock cress.
In northern Indiana he found this butterfly abundant in April at the
time of the blossoming of _Arabis lyrata_. The butterflies would be
flying about, easily seen in the air. Then they would suddenly
disappear and could be found only after the most careful search. They
had simply lit upon the flower heads, when the flower picturing of the
under surface of the wings blended perfectly with the appearance of
the clustered flower.
"The green markings of the under side of the wing," writes Dr.
Hancock, "are so arranged as to divide the ground color into patches
of white, which blend with or simulate perfectly the petals of the
clustered flowers. The eyes of the butterfly are delicate pale green
and the antennae are whitish, all of which adds to the effectiveness
of the blend. The flowers of _Arabis_ have white petals with the
centre yellowish green, as is also the calyx. There is a shade of pink
outside the base of the petals. All in all, the adaptation of insect
to flower here displayed is one of rare exquisiteness."[C]
[C] "Nature Sketches in Temperate America", p. 83.
Dr. Hancock found that the butterflies were able to cling on the
flowers during strong winds very persistently, so that even when a
storm blew across the sand dunes they were likely to remain in
position. They also have the instinct to rest very quietly after they
have lit upon the clustered flower heads.
=The Olympian Orange-tip=
_Synchloe olympia_
In various parts of the Southern states there is at least one other
Orange-tip butterfly which is found occasionally in connection with
the Falcate Orange-tip. It was named Olympia many years ago by William
H. Edwards. It is a delicate white species marked with black and
yellow very lightly both above and below, the yellow showing only on
the under side of the hind wings and that part of the front wing which
is exposed when the insect is at rest. Strictly speaking, this is not
an Orange-tip because the orange color is lacking in both sexes.
This is rather a rare species which occurs occasionally from the
Atlantic states to the Great Plains south of a line drawn from
northern Maryland to northern Missouri. Like its allies the larvae
feed upon various cruciferous plants, the hedge mustard being one of
these and the adults visit the flowers of the same family. They
doubtless have habits similar to those of the Falcate Orange-tip, and
the extreme delicacy of color must render them practically invisible
when resting upon the small white flowers of most crucifers.
[Illustration: _From a drawing by Mary E. Walker_ _See page 72_
THE TIGER SWALLOWTAIL
(Reduced)]
[Illustration: _From a drawing by W. I. Beecroft_ _See page 83_
THE IMPORTED CABBAGE BUTTERFLY
Caterpillar, chrysalis, and butterflies]
Most of the Orange-tip butterflies are found on the Pacific Slope,
ranging from Alaska southward, several of them being especially
abundant in the western mountain regions. About eight species are
recognized as belonging to our fauna, some of which have several
well-marked varieties.
_Synopsis of the Orange-tips_
_Falcate Orange-tip_ (_Synchloe genutia_, _Anthocaris genutia_ or
_Euchloe genutia_). Expanse 1 2/5 inches. Tips of front wings
projecting in a hooked angle. Orange blotch on upper surface near tip
in male, absent in female.
_Olympian Orange-tip_ (_Synchloe olympia_, _Euchloe olympia_ or
_Anthocaris olympia_). Expanse 1 1/2 inches. Wings white above in both
sexes with greenish black markings at base of all wings and along
front margin of front wings, especially at apex. No orange patch.
THE TRIBE OF THE YELLOWS
A large proportion of our most abundant and conspicuous butterflies
belong to the Tribe of the Yellows. Sometimes it is called the Tribe
of the Red-horns because the antennae of the living insects are so
often red. These insects vary in size from the large Brimstones or
Cloudless Sulphurs, expanding three inches, to the delicate little
Dainty Sulphur, expanding scarcely an inch. The distinctive
characteristics of the tribe are found in the very gradual enlargement
of the joints of the antennae that form the club, and the stout palpi,
the last joints of each of the latter being short.
=The Brimstone or Cloudless Sulphur=
_Callidrayas eubule_
Practically all northern butterflies are variously marked in different
colors, while the butterflies of tropical regions are commonly tinted
in monotone, though often showing a splendid iridescence. One with
very little experience can tell the look of a tropical butterfly and
would be likely to say at once that the Cloudless Sulphur is one of
these. The upper surface of the wings of the male is a clear plain
sulphur with merely the narrowest possible fringe of brown around the
margin made only by the colored marginal scales. The under surface is
lighter and sparsely dotted in brown. In the females the marginal
brown takes on the shape of a series of small crescents and there is a
single round brown eye-spot just in front of the middle of each front
wing.
While the Cloudless Sulphur is without doubt essentially a tropical
species it has an extraordinary geographical range. It is extremely
abundant in Mexico, Cuba, and the tropical zone in South America. It
extends south even to northern Patagonia and north to New England,
Wisconsin, and Nebraska.
Presumably in the tropics this species breeds continuously, one
generation following another in regular succession unless interrupted
by drought or other natural phenomena. In our Southern states there is
more or less interruption by the winter season, so that it is commonly
considered to have only two broods, the butterflies hibernating.
Farther north there is probably only one brood in summer, and perhaps
not even that in the extreme limit of its range. For there is pretty
good evidence that the specimens seen in the Northern states are
migrants from the south, coming singly or in scattered flocks in early
summer, and if they lay eggs the butterflies of the new generation
return south in autumn. But the precise conditions are not well known
and need careful observations in various localities.
The life-story of a generation of these butterflies is much like that
of the other Yellows. The eggs are laid, one in a place, on the
leaflets of various species of wild senna (_Cassia_) and soon hatch
into cylindrical caterpillars that devour the tender leaflets. In a
few weeks the caterpillars mature and change to curious and
characteristic chrysalids. The head projects in the shape of a cone
and the back is so concave as to give the side view of the chrysalis a
very striking appearance.
Like so many of the Yellows this butterfly is sun-loving and social in
its habits. Great numbers flock together, their large size and bright
coloring rendering them very conspicuous. They often alight on the
ground to sip moisture when they have been likened to beds of yellow
crocuses. They also fly long distances in flocks that attract much
attention. It is likely that the northward distribution takes place in
summer through such migrating hosts.
_Other Sulphur Butterflies_
The Large Orange Sulphur is a closely related butterfly of about the
same size, in which the coloring is uniformly orange-yellow instead of
lemon-yellow. It also belongs to the tropics, occurring in our extreme
Southern states and ranging occasionally as far north as Nebraska.
The Red-barred Sulphur is another splendid butterfly, somewhat larger
than the Brimstone, which is easily distinguished by the broad reddish
bar across the upper surface of the front wings. It is tropical but
migrates rarely even as far north as Indiana, Illinois, and Wisconsin.
=The Dog's-head Butterfly=
_Meganostoma caesonia_
The Dog's-head butterfly furnishes one of the most remarkable examples
of accidental resemblance in wing markings that can be found in the
whole order of scale-winged insects. It is comparable with the skull
and crossbones on the back of the death's-head moth. In the butterfly
the middle of the front wings has a broad band of yellow against a
black margin on each side and the yellow outlines make an excellent
silhouette of the profile of a poodle with a large black eye-spot in
exactly the proper place. The females are less brightly colored than
the males but they still show the dog's-head silhouette.
This is a southern species, which occasionally strays as far north as
New York City, New Hampshire, Wisconsin, and Iowa. The larvae feed on
species of Amorpha and are believed to be three-brooded in southern
regions where the butterfly occurs.
The California Dog's-head is even more beautiful than the southern
species. It is remarkable for its pink and purple iridescence--a
characteristic which is not common in the butterflies of the Yellow
and the White Tribes. The silhouette of the Dog's-head is less perfect
than in the more eastern species, and the yellow color tones are more
tinged with orange. The female is strikingly different, the wings
being plain pale yellowish buff marked only with a round blackish
eye-spot near the middle of each front wing and the barest suggestion
of a dark line around the extreme margin.
=The Clouded Sulphur=
_Eurymus philodice_
It is an interesting fact that the butterfly which one is most likely
to find in fields and along roadsides during practically all the weeks
of summer has seldom if ever been noted as a destructive insect. The
Clouded Sulphur is probably the commonest species in its group. There
may be times when the White Cabbage butterfly or other forms are more
abundant, but the Clouded Sulphur retains its place season after
season, with comparatively little noticeable variation in its numbers.
This is doubtless an illustration of an insect which has established
such relations with its food plants and its various insect and other
enemies that it remains in a fairly stable equilibrium--an example of
what is often called the balance of nature.
The Clouded Sulphur is about the only medium-sized yellow butterfly
generally found in the Northeastern states. The adults may be seen
from spring until autumn. They lay eggs upon clover and other plants.
These eggs hatch into small green caterpillars that feed upon the
leaves and are protectively colored so they are comparatively seldom
seen. When the food plant is disturbed they drop to the ground,
crawling up again upon stems and leaves when the disturbance is over.
These caterpillars moult several times during their growth. When full
grown they find such shelter as they are able and each spins a silken
web over part of the surface. It then fastens its hind legs into this
web and later spins a loop near the front end of the body. It pushes
itself beneath this loop and waits for several hours before the skin
breaks open along the back and is gradually shuffled off revealing the
chrysalis in position. A week or two later the fully developed
butterfly emerges from the chrysalis.
These yellow butterflies lend a distinctive charm to our summer
landscapes. They are constantly to be seen fluttering from place to
place, lightly visiting flowers of many kinds from which they suck the
nectar, and gathering in great colonies by roadside pools where they
seem to sip the moisture. There are many references to this insect in
the writings of New England authors. It evidently was an especial
favorite of James Russell Lowell who has often referred to it in
passages like this:
"Those old days when the balancing of a yellow butterfly over a
thistle bloom was spiritual food and lodging for a whole forenoon."
=The Orange Sulphur=
_Eurymus eurytheme_
Were one able to take a Clouded Sulphur butterfly and change the
yellow to a deep orange color he could easily make a specimen that
would pass for the present species. The resemblance is very
remarkable and shows the close affinity between these two beautiful
insects.
Like so many others of this group the Orange Sulphur is essentially a
tropical species. In the eastern United States it is rarely found
north of latitude forty degrees, but south of that it becomes
increasingly abundant as one approaches the tropics. It occurs from
the Carolinas to Texas, and over the great range in which it lives it
takes on many different forms and habits. It is one of the most
remarkable examples of variation in coloring exhibited by any of the
butterflies. Nearly a dozen species names have been given to its
various disguises, all of which are now recognized as synonyms. In the
more northern regions where it is found, only one of these forms
usually occurs, but in other places bright yellow and pale white
varieties are found.
The life-history of this butterfly along latitude forty degrees is
very similar to that of the Clouded Sulphur. There seem to be usually
two broods and the caterpillars live upon leguminous plants,
especially alfalfa, buffalo clovers, wild senna, and other species of
Trifolium and Cassia. Apparently also it hibernates in both the
caterpillar and the butterfly stages.
In the extreme Southwest--as on the plains of Texas--the vegetation
dries up completely in summer so that there is no succulent leafage
for the caterpillars to live upon. In such cases the insect must
aestivate rather than hibernate. This species apparently succeeds in
doing this by having the caterpillars go into a more or less lethargic
condition in which they pass the summer. The adult butterflies utterly
disappear in June and are not seen again until early in autumn when
the autumn rains have started the growth of vegetation anew. The
insects then make up for lost time and produce several broods in rapid
succession.
In the Imperial Valley of California this butterfly is a serious pest
to alfalfa growers. It continues to reproduce throughout a very long
season, one brood following another from March until December, and in
mild winters there seems sometimes to be practically no cessation of
its activities. Mr. V. L. Wildermuth found that the development of a
generation in breeding cages in this valley varied from twenty-two to
forty-four days, the latter in cool, the former in hot weather. The
stages in the first and the third broods in spring varied thus: Egg,
first six days, third four days; larva, first thirty days, third
twelve days; chrysalis, first eight days, third five days. In this
case the first generation extended from March 15 to April 30 and the
third from May 28 to June 20. After the fourth brood of butterflies
there was such an overlapping of the various stages that it was
impossible to distinguish the broods.
=The Pink-edged Sulphur=
_Eurymus interior_
This beautiful butterfly was first made known to the world of science
by Louis Agassiz, the great naturalist who did so much to arouse a
scientific interest among Americans. He found it on a famous
expedition to the northern shores of Lake Superior, which not only
served to bring to light many interesting phases of geological history
but also laid the foundation for the copper mining industry which has
since become so important in that region. The butterfly thus brought
to light has been found to be a characteristic northern species,
occupying a rather narrow belt nearly along the fiftieth degree of
latitude and extending west almost to the Pacific Coast. The species
is occasionally taken as far south as the White Mountains and there
are indications that in this region there are two broods a year. The
male butterflies are known at once by a beautiful pink edge on all the
margins; they bear otherwise a close resemblance to our common Sulphur
Yellow. The females are much lighter in color, often having no black
markings on the upper surface of the hind wings.
=The Black-bordered Yellow=
_Eurema nicippe_
This is essentially a tropical butterfly which has spread out over
most of our Southern states where it is abundant and widely
distributed. It adds a distinct touch of color and life to many
landscapes when the butterflies swarm by thousands upon clover
blossoms and other low vegetation. The eggs are laid upon the leaves
of clover and more especially upon some common species of Cassia, such
as wild senna. Each egg soon hatches into a small greenish cylindrical
worm, colored and striped in such a way that as it rests upon the leaf
it is easily overlooked. This larva develops rapidly and soon becomes
about an inch and a quarter long, being rather slender and fairly
smooth. It now spins a bit of silk upon a twig or some similar support
and also the frailest sort of a silken loop to pass around its back.
It now entangles its hind feet in the bit of silk and soon casts off
its last caterpillar skin, emerging as a curious looking chrysalis
about three quarters of an inch long with a remarkable pointed
projection on the front of the head. When seen through a hand lens
this pointed projection and the well-developed characteristic wing
sheaths give the chrysalis a remarkable resemblance to some of the
twig hoppers or Membracids. The colors vary considerably with the
surroundings but are commonly toned in various shades of green and
yellow brown.
A little later each chrysalis breaks open to disclose one of the
beautiful butterflies.
The conditions under which this butterfly lives at the limit of its
northern range are not well determined. It is probable that many of
those seen here have flown from considerably farther south, and that
these migrants lay eggs from which a brood of butterflies develops,
these native born appearing late in summer. Presumably the latter
hibernate, but whether they can do this successfully under the
rigorous conditions of our northern winters has never been determined.
In fact, Scudder wrote some years ago that no caterpillars had ever
been found in New England. Here is an interesting opportunity for some
young observer to make a real contribution to science.
=The Little Sulphur=
_Eurema lisa_
Were one to imagine a Clouded Sulphur butterfly reduced to half its
usual size and built with a corresponding delicacy of structure, one
would have a pretty good idea of the beautiful little creature called
by the above name. I well remember in my college days taking what was
probably the first of these butterflies ever collected in the region
of our Michigan college. It was a prize that very likely had wandered
north from Indiana but which served to add much glory to the little
collection in which I took such pride, for this is essentially a
southern species. In many regions of the South it is so abundant that
it can be taken by any one. It ranges from coast to coast and extends
south into the tropics. In the eastern region it is found from
southern Wisconsin to southern New England, occurring sparingly and
locally in various places along the line thus indicated.
The food plant of the species is chiefly wild senna or other kinds of
Cassia. The mother butterflies deposit the eggs singly on leaves or
stems, generally on the small leaflets of the compound leaf. Less than
a week later each egg hatches into a cylindrical greenish caterpillar
that feeds upon the leaflets in a characteristic fashion. Instead of
devouring the blade from the margin inward it gnaws narrow strips
between the smaller veins. When not feeding, the caterpillars protect
themselves from observation by birds or other enemies by resting
motionless along the stem of the leaflet or else along the midrib on
the under side. As is well known the leaflets of Cassia, like other
leguminous plants, close at night. It is probably on this account that
these caterpillars feed chiefly by day. The general green color of the
skin and the straight stripe along the side help to make this
caterpillar very inconspicuous when it is at rest.
When full grown the caterpillar reaches a length of three quarters of
an inch. It now finds some bit of shelter on which it spins a bit of
flat web and a silken loop to hold it in place as it becomes a
chrysalis. It then changes and remains quiescent for ten days or more
when it emerges as the dainty butterfly.
Notwithstanding its abundance and its successive broods its
life-history is none too completely worked out. There is still
opportunity for careful observations upon the way in which it passes
the winter in various parts of its range. While in the South it
apparently hibernates as an adult, this fact is not certain in the
more northern localities.
Notwithstanding its diminutive size this butterfly has been known to
swarm in such enormous numbers as to seem a veritable cloud. The most
notable record of this has been quoted by Scudder in connection with a
swarm that invaded the Bermuda Islands, in 1874, on the first day of
October. It was described in these words:
"Early in the morning several persons living on the north side of the
main island perceived, as they thought, a cloud coming over from the
northwest, which drew nearer and nearer to the shore, on reaching
which it divided into two parts, one of which went eastward and the
other westward, gradually falling upon the land. They were not long in
ascertaining that what they had taken for a cloud was an immense
concourse of small yellow butterflies, which flitted about all the
open grassy patches in a lazy manner, as if fatigued after their long
voyage over the deep. Fishermen out near the reefs, some few miles to
the north of the islands very early that morning, stated that numbers
of these insects fell upon their boats, literally covering them."
As is the case with so many of the related yellow butterflies there is
an albino variety of this species. It has been given the variety name
_alba_ although it is really a pale yellow rather than a true albino
form.
=The Dainty Sulphur=
_Nathalis iole_
While the Little Sulphur butterfly seems about as delicate a creature
as one could ask to see, it loses that distinction when it is compared
with the still smaller Dainty Sulphur. The latter expands scarcely an
inch when its wings are stretched apart, and its slender body and
antennae help to give the suggestion of extreme delicacy. There is
more marking of black upon the sulphur-yellow wings than is the case
with the larger form, the upper portion of the front wings showing
only a broad yellow band upon a background of darker color. The under
wings are nearly all yellow.
_Synopsis of the Yellows_
_Brimstone_ or _Cloudless Sulphur_ (_Callidryas eubule_ or
_Catopsilia eubule_). Expanse 2 1/2 inches. Upper surface of male
clear, light, sulphur yellow. Female with a brown spot in front of
middle of each front wing and a narrow brown margin on all the wings.
Under surface deeper yellow with sparsely scattered brownish dots.
_Red-barred Sulphur_ (_Callidryas philea_ or _Catopsilia philea_).
Expanse 3 inches. Easily known by the reddish orange bars on the
sulphur-yellow wings.
_Large Orange Sulphur_ (_Callidryas agarithe_ or _Catopsilia
agarithe_). Expanse 2 1/2 inches. Distinguished at once by its uniform
orange-yellow color.
_Dog's-head Butterfly_ (_Zerene caesonia_, _Colias caesonia_ or
_Meganostoma caesonia_). Expanse 2 1/4 inches. Upper surface yellow
with black inner and outer borders on front wings and black outer
border on hind wings. The black and yellow of each front wing so
combined as to make a distinct dog's head with black eye.
_Clouded Sulphur_ (_Eurymus philodice_ or _Colias philodice_). Expanse
2 inches. Upper surface sulphur yellow with blackish borders, the
yellow brighter in the male than in the female. Male with line between
yellow and black distinct, a black spot just in front of the middle of
each front wing and an orange spot near the middle of each hind wing.
Under surface of male deeper yellow, with spots as on the upper
surface but without black margin, and with a row of sub-marginal
brownish dots on each wing. Female with upper surface more generally
suffused between marginal mark and the yellow part with more or less
duskiness both above and below. Spots on each wing much as in male. In
the white form of the female (_pallidice_) the yellow is replaced by
white.
_Pink-edged Sulphur_ (_Eurymus interior_). At once distinguishable
from _philodice_ by the narrow pink edge of all the wings, showing
both from above and from below, slightly smaller as a rule.
_Orange Sulphur_ (_Eurymus eurytheme_ or _Colias eurytheme_). Expanse
2 1/4 inches. Much like Clouded Sulphur in markings except that
prevailing color-tone is orange yellow.
_Black-bordered Sulphur_ (_Eurema nicippe_, _Xanthidia nicippe_ or
_Terias nicippe_). Expanse 2 inches. Upper surface of wings bright
orange with a small black dash in front of the middle of each front
wing and a broad black border on all the wings. In the females the
borders are interrupted at the rear. Under surface slightly brownish
yellow, minutely striated and clouded when exposed when the butterfly
alights.
_Little Sulphur_ (_Eurema euterpe_, _Eurema lisa_, _Xanthidia lisa_ or
_Terias lisa_). Expanse 1 inch. Easily known by its small size and
delicate structure. Upper surface of wings yellow with distinct black
borders. Under surface yellow with indistinct spots.
_Dainty Sulphur_ (_Nathalis iole_). Expanse 1 inch. Easily known by
its small size and narrow yellow wings with black bars across the
outer angles and black bands across the back border of the front wings
and the front border of the hind wings.
THE NYMPHS
FAMILY _Nymphalidae_
A large proportion of our most familiar butterflies belongs to this
family. The Fritillaries, the Angle-wings, the Sovereigns, and the
Emperors are tribes in which practically all the species are of medium
or large size. The Crescent-spots include a few which are rather
small.
The combinations of characters by which the Nymph family is
distinguished are these: Front legs dwarfed into lappets; scaly
antennae; veins of fore wings not swollen at base; wings of normal
shape, not much longer than wide. Larvae cylindrical, but varying
greatly in form, color, and skin coverings. Chrysalids angular in
most species, in others rounded.
The stories of the lives of the many members of this family vary
considerably, as one would expect from their variety and numbers. We
may take, however, the life of the familiar Antiopa or Mourning Cloak
as typical of the group. Briefly summarized, its story may thus be
told:
During sunny days in spring one may often see a beautiful purple-back
butterfly, having a cream-colored border along the outer margin of its
wings, flying leisurely about, in the vicinity of woods and in the
open fields. This insect is called the Antiopa or Mourning Cloak; it
is represented natural size in plate opposite page 145. It has passed
the winter in this adult condition, having found shelter in some
retreat where it is not directly exposed to the storm and stress of
the weather.
When the leaves of the elm, willow, and poplar trees are nearly
expanded, these butterflies deposit their eggs upon the twigs. These
eggs are laid in clusters encircling the twigs, there being twenty or
more in each cluster. In the act of oviposition, the butterfly keeps
her wings spread out, moving the body and abdomen about as the placing
of the eggs necessitates.
About two weeks after the clusters of eggs are thus laid upon the
twigs of the food plant, they hatch into small blackish caterpillars,
each emerging from the egg shell through a small hole that it eats out
of the upper surface. They thus enter upon the second stage in their
life-history--the larva or caterpillar stage. As soon as hatched, they
crawl to the nearest leaf upon which they range themselves side by
side, with their heads toward the margin of the leaf. They feed in
this position, nibbling at the green surface of the leaf-blade and
leaving the network of veins untouched.
[Illustration: _See page 76_
THE ZEBRA SWALLOWTAIL
Summer form: upper surface, above; under surface, below]
[Illustration: _From a drawing by Mary E. Walker_ _See Page 101_
THE CLOUDED SULPHUR BUTTERFLY
Caterpillar and butterfly on red clover plant. (Reduced)]
[Illustration: _From a drawing by Mary E. Walker_ _See page 76_
ZEBRA SWALLOWTAILS
Visiting blossoming branches of the pawpaw tree. (Reduced)]
[Illustration: _See pages 97-115_
SOME OF THE TRIBE OF YELLOWS
upper surfaces at left; under surfaces at right
(1) The Black-bordered Yellow--male;
(2) the Clouded Sulphur--male;
(3) the Orange Sulphur--female;
(4) the Dog's-head--male]
These caterpillars continue to feed in this manner for about a week,
remaining side by side when feeding, and marching in processions from
one leaf to another as the food supply is exhausted. Wherever they go,
each spins a silken thread on the surface traversed, so that the
combination of all the threads makes a sort of carpet that serves as a
foothold for the caterpillars. At the end of the week they moult or
cast their skins, a process in which the skin of each larva splits
open along the back, and the larva crawls out covered with a new skin
that had been formed beneath the old one. This new skin stretches
somewhat after the caterpillar emerges, so that the insect is able to
increase considerably in size. At the period of moulting, the
caterpillars remain quiet for a short time, but they soon become
active again and begin feeding with increased voracity.
[Illustration: Eggs of Mourning-Cloak, laid in a cluster on a
twig. (From Holland).]
During the next three weeks, this moulting process is repeated three
times, the caterpillars becoming larger each time, and leaving their
cast skins upon the denuded twigs. They soon scatter more or less over
neighboring leaves, but remain in closely associated colonies. As they
increase in size, they eat more and more of the leaf substance; when
half grown, they devour all but the midrib and the side veins; but
when they get larger, only the midribs are left.
The carpet web that they form becomes more conspicuous as the
caterpillars become full grown. They then leave the tree or shrub on
which they have been feeding, and scatter about, seeking some
sheltered situation. Having found this--perhaps beneath a stump or
along the under side of a fence--each caterpillar spins a web of silk
along the surface. It then entangles the hooked claws of its hind legs
in the silken web, and lets its body hang vertically with the head end
curved upward. It remains in this position some hours before the skin
along the back just behind the head splits apart and is gradually
wriggled upward, until finally it is all removed and there hangs in
place of the caterpillar a peculiar object having no definite form.
But it rapidly assumes a definite form--that of the chrysalis--which
is grayish brown, different specimens varying somewhat in shade.
In this quiet chrysalis, the insect is apparently almost as inert as a
mummy. If you touch it it will wriggle a little, but otherwise it
hangs there mute and helpless. On the inside, however, the tissues are
being made over in such a wonderful way that, in about two weeks, from
the mummy case into which the caterpillar entered there comes a
beautiful butterfly.
When this butterfly first breaks through the mummy shell, its wings
are very small, although its body, antennae, and legs are well
developed. By means of the latter, it clings to the empty chrysalis,
while its wings expand. At first these wings are short, but as soon as
the insect takes a position in which the wings hang downward, they
begin to expand, and soon reach full length, but are more or less
crumpled longitudinally, and the front wings are not so wide as the
hind ones, hanging limply inside the latter.
After the butterfly has thus reached its full form and size, it crawls
from the chrysalis to some neighboring support, where it rests quietly
for half an hour or more. During the latter part of this time it
exercises its unused muscles by slowly opening and closing its wings,
until it finally flies away.
THE TRIBE OF THE FRITILLARIES
This is one of the most distinctive tribes of the family of Nymphs.
The clubs of the antennae are about twice as long as broad and
curiously spoon-shaped. The palpi are large and bushy, with the last
joint very short. Most of the species are rather large and practically
all are beautifully mottled in various tones of brown, red, black, and
silvery gray. A large proportion of our midsummer butterflies are
members of this tribe.
=The Gulf Fritillary=
_Agraulis vanillae_
In tropical America there is a genus of butterflies called Agraulis.
These are fairly large insects, approximating the size of the Viceroy,
which show most beautiful colors in the tropical sunshine. One member
of this genus has come north to our Southern states, and is
occasionally found as far up as Virginia and southern Illinois,
extending below this from ocean to ocean. It reveals on its upper
surface the most exquisite tints of iridescent purples and browns,
suggesting by its form and color as thus seen a tropical species. The
lower wing surface, when the wings are closed in their natural
position, shows only a spangled effect of silver-white and brown,
which is very suggestive of the under surface of our northern Spangled
Fritillaries. So this beautiful species may fittingly be called the
Gulf Fritillary, carrying over from the north some of its peculiar
beauty and connecting with the equally distinctive beauty of the
tropical south.
Like so many other southern butterflies the eggs of this species are
laid upon the leaves of passion vines. The caterpillars develop very
rapidly and when matured are yellowish or brownish yellow, striped
with darker lines along the back and sides. There are black branching
spines, arranged in rows beginning on the head and running backward on
the body. The whole cycle of life from egg to butterfly may take place
within the short period of a month and one brood succeeds another in
so irregular and rapid a fashion that it is difficult to determine
definitely the number of broods in a season.
=The Variegated Fritillary=
_Euptoieta claudia_
There is something in the appearance of the upper surface of this
butterfly that suggests the other Fritillaries on the one hand and the
Emperors on the other. The coloring and marking is a bit like the
former and the shape of the wings like the latter. The general color
is a golden brown with darker markings arranged in bands and eye-spots
in a rather complicated pattern. The under surface, so far as it is
exposed when the butterfly is at rest, is a beautiful marbled
combination of gray and brown which is probably distinctly
obliterative in the haunts of these insects. The front wings have the
outer margin concave in the middle, giving a special prominence to the
shape of each front outer angle.
This butterfly is a southern rather than a northern species, but it is
found occasionally from Montana to Massachusetts and southward to
Arizona, Mexico, and Florida. Even in northern Indiana it is very
seldom found and is considered rare in the southern part of that
state. Around Buffalo, New York, it is also rare and is not common in
the vicinity of New York City. In the more Southern states, however,
it is abundant and extends well through the continent of South
America.
There is considerable evidence to indicate that this butterfly
hibernates as an adult. In the more southern regions it probably also
hibernates in other stages, especially the chrysalis and the larva. In
regions where it is double-brooded, as it appears to be in the
latitude of New York City, the seasonal history seems to run something
like this: the partly grown caterpillars which have passed the winter
in shelter at the surface of the soil feed upon the leaves of violets
and certain other plants. They change to chrysalids, probably in May,
and emerge as butterflies in June. These butterflies lay eggs for a
summer brood of caterpillars which may feed upon the leaves of
violets, May apples, portulaca, and stonecrop. They grow into
cylindrical worms of a general reddish yellow color, marked by
longitudinal stripes of brown upon the sides and a row of whitish dots
upon the back. They become matured in time to disclose the butterflies
of the second brood in August and September. Presumably these
butterflies lay eggs that develop into caterpillars which hibernate
when partially grown.
Farther south there are probably three broods a year and hibernation
may take place in various stages. There is good opportunity for
careful work in determining the life-history of the species in
different latitudes. The butterfly is found in much the same
situations as the other Fritillaries, flying over meadows and along
the borders of woods.
=The Diana Fritillary=
_Argynnis diana_
This magnificent butterfly differs from the other Fritillaries in the
fact that the females are so unlike the males that only a skilled
naturalist would even guess that they are related. Both sexes are
rather rare and are found only in a comparatively narrow range
extending from West Virginia to Missouri, northward to Ohio and
Indiana, and southward to Georgia and Arkansas.
This species was first described by Cramer a long time ago from
specimens of the male sex. It was later described by Say and other
writers all of whom saw only the males. The other sex was first
recognized by William H. Edwards, whose account of its discovery as
given in his splendid work on the Butterflies of North America is
worth quoting:
"No mention is made of the female by any author," wrote Mr. Edwards,
"and it seems to have been unknown till its discovery by me in 1864 in
Kanawha County, West Virginia. On the 20th August, I saw, for the
first time, a male hovering about the flowers of the iron-weed
(_Vernonia fasciculata_), and succeeded in taking it. Two days
afterwards, in same vicinity, while breaking my way through a dense
thicket of the same weed, hoping to find another Diana, I came
suddenly upon a large black and blue butterfly feeding so quietly as
to allow me to stand near it some seconds and watch its motions. It
seemed to be a new species of Limenitis, allied to Ursula, which it
resembled in color. But on taking it, I saw it was a female Argynnis,
and the general pattern of the under wing left little doubt of its
affinity to the Diana male, despite its total difference in color and
of upper surface. Subsequent captures confirmed this conjecture, and
out of the large number that have since been taken the males have been
of the known type and the females black, with no tendency in either to
vary in the direction of the other.
"When my attention was called to the species I found it not very
uncommon, always upon or near the iron-weed, which is very abundant
and grows in rank luxuriance upon the rich bottom lands of the Kanawha
River, frequently reaching a height from eight to ten feet and in
August covered by heads of purple flowers that possess a remarkable
attraction for most butterflies. Both sexes are conspicuous, the males
from the strong contrast of color and the females from their great
size and the habit of alighting on the topmost flower and resting with
wings erect and motionless. It is an exceedingly alert and wary
species, differing in this from our other Argynnids. At the slightest
alarm it will fly high into the woods near which, upon the narrow
bottoms or river slopes, it is invariably found. It is a true southern
species, sensitive to cold, not to be looked for in the cooler part of
the morning but flying down from the forest when the sun is well up.
From eleven to three o'clock is its feeding time."
The life-history of this fine butterfly is similar to that of the
lesser Fritillaries. The butterflies appear from midsummer onward, the
males preceding the females, and the eggs are laid on or near violets
in August or September. The larvae hibernate and mature early the
following summer. As they approach the chrysalis stage they are rather
large velvety black caterpillars with brown heads and rows of fleshy
barbed spines that show an orange tint at their bases. There is thus
but one generation each year.
=The Regal Fritillary=
_Argynnís idalia_
The Regal Fritillary, fresh from the chrysalis, still showing the
marvelous sheen of its iridescence, furnishes one of the most
beautiful exhibitions of color in the world of nature. Over the whole
wing surface there are tiny scales that reflect the sunlight in an
almost dazzling manner, giving a distinct purplish tone especially to
the hind wings.
The Regal Fritillary is one of the largest butterflies of the
distinctive group to which it belongs. The wings expand some three
inches and the rather thick body is more than an inch long. The
general ground color of the wings is brown, with distinct markings of
blackish which in the hind wings almost obscure the brown. On each of
the latter as seen from above there is a distinct row of cream-colored
spots across the middle, duplicated by a similar row of brown spots
near the margin. The under surface of both pairs of wings is much
lighter and thickly mottled all over with light cream-colored spots of
a large size and more or less triangular shape. (_See frontispiece._)
Like the other Argynnids, the Regal Fritillary is single-brooded
during the year and it has a rather remarkable longevity in each stage
of its life. The newly hatched caterpillars go into hibernation and
live through the winter without feeding, finding shelter at the
surface of the ground, especially beneath the leaves of violets which
form their chosen food plants. When the snow has disappeared and the
warmth of the spring sun brings them out of their winter lethargy
these tiny caterpillars feed upon the violet leaves and grow slowly
for several weeks. They then change to chrysalids, the time for doing
this varying considerably with the individual and doubtless with the
warmth of the situation in which each is living. The length of time
spent in the chrysalis varies also, but in general it seems to be less
for those which develop into male butterflies than for the females. It
is a curious fact that the former may be found for nearly two weeks
before any of the latter appear.
The first butterflies of this species are usually disclosed from the
chrysalis late in June or early in July. They continue to come forth
for several weeks, apparently until nearly the middle of August. They
lead a leisurely life, visiting freely the flowers of goldenrod,
iron-weed, boneset, Joe Pye weed, and especially swamp milkweed. They
are most likely to be found in lowlands and along the borders of
swamps where these favorite flowers are growing. It evidently requires
some time for the eggs to develop within the ovaries, for the
butterfly cannot begin laying these until the latter part of August.
They apparently are normally deposited on the under side of violet
leaves, although so far as I know no butterfly has been seen thus
laying her eggs. It would be an interesting point for some young
observer to determine. Even the eggs take a long time to develop, not
hatching for three or four weeks after they are laid. When they do
hatch the tiny caterpillars seem not to eat at all but to go directly
into hibernation.
These butterflies are to be found in their preferred habitats almost
any time during July, August, and September. Apparently many of them
live as adults for nearly three months so that whether we consider the
egg, the larva, the chrysalis, or the adult we have in this species an
unusual duration of life. This is doubtless an adaptation to the fact
that the species must get through the year with only one brood.
This unity of habit with no such variations as occur in many
butterflies with a wider range north and south is apparently
correlated with the distribution of this butterfly. It is found in a
belt of territory running from New England and the Atlantic states
westward at least to Nebraska along a line which approximates the
annual isotherm of fifty degrees Fahrenheit.
=The Great Spangled Fritillary=
_Argynnis cybele_
To one who wanders much in the woods and open fields there are few
summer scenes more characteristic of the season than that of a group
of milkweeds in full flower, surrounded by a host of brown butterflies
busily sucking the nectar from the curious pink blossoms. There are
likely to be several species of these winged creatures, but in many
regions of America the largest and most conspicuous will generally be
the Great Spangled Fritillary. This butterfly is easily recognized by
its large size and its combination of two colors of brown, with
whitish or silverish spots scattered over the lower surface of the
wings.
The life-history of this insect is of peculiar interest on account of
the way in which it passes the winter. The mother butterfly remains
upon the wing through many weeks in summer, so that toward the end of
August or early September a large proportion of the specimens have a
decidedly frayed appearance. They are patiently waiting for the season
of the year when they can deposit their eggs, apparently knowing by
instinct that this must not be done until early autumn. When the
proper season arrives they lay their eggs upon the leaves or stems of
wild violets, apparently without much reference to the particular
species. Sometimes they have been reported simply to drop the eggs
loosely upon the violet plant with no attempt to fasten them in place.
Having thus deposited the eggs the mother butterflies soon die.
It would not seem strange if these eggs remained unhatched until the
following spring, but the fact is that the eggs hatch very soon into
small caterpillars that eat off part of the shells in order to escape
and sometimes eat also part of the shell remaining after they have
emerged. Various good observers have apparently established the fact
that these tiny caterpillars eat nothing else before winter sets in.
It seems curious indeed that they should not nibble at the leaves or
stems of the violet plants in order to be slightly prepared for the
long fast that awaits them before they will find food upon the young
buds the following spring. The case is somewhat similar to that of
the common tent caterpillar which becomes a fully formed caterpillar
within the egg shell before the end of autumn, but remains unhatched
until the following spring. In the present case the caterpillar
hibernates outside of the egg shell rather than within it.
When at last the warm sunshine of spring starts the violets into new
growth the tiny caterpillars begin feeding upon the succulent tissues.
They nibble away day after day for a week or more before they become
so large that they have to cast their skin for the first time. They
then feed again and continue this process of feeding and moulting
until early in summer. They are likely to hide themselves during
daylight and have the reputation of being difficult to rear under
artificial conditions.
The full-grown caterpillar wanders along the surface of the ground in
search of suitable shelter for the chrysalis period. When it comes to
a large stone with sides projecting more or less horizontally or a log
lying upon the ground or even a large piece of loose bark it is likely
to stop and change to the pupa or chrysalis. In this condition it is
dark brown in color and well covered with thickened tubercles,
especially along the back of the abdomen.
About a fortnight later the chrysalis breaks open and the fully
developed butterfly comes forth. It rests quietly for a time while its
wings expand and the tissues harden and then sallies forth for its
long period of flight; for this insect is single-brooded in the
Northern states at least and the butterflies that thus mature late in
June or early in July are likely to remain alive until early in
September. So they have a comparatively long life for a butterfly that
does not hibernate as an adult.
=The Silver-spot Fritillary=
_Argynnis aphrodite_
Our brown Fritillaries are seldom found without several species
mingling together. This is not strange, for they have similar habits
throughout their entire lives. So when you see a bevy of butterflies
collected around the midsummer blossoms of the milkweed, you are
pretty sure to find that the Great Spangled Fritillary is associated
with the Silver-spot and probably one or two other related forms. The
Silver-spot is generally decidedly smaller than the one first named
and the surest way to be certain of it is to look on the under side of
the hind wing and see whether there is a broad band of buff between
the two outer rows of silver spots. If this band has disappeared or is
nearly all taken up by the brown ground-color of the wing, you may be
pretty sure we have the Silver-spot Fritillary.
When one has firmly fixed in mind the life cycle of one of these
butterflies, one has a model after which to fashion the rest, for our
several species are remarkably alike in this respect.
The Silver-spots are on the wing for several weeks in summer. During
the latter part of this time the females lay eggs upon violet leaves.
These eggs shortly hatch into caterpillars that go directly into
hibernation, taking no food before winter sets in. The following
spring they feed upon violet leaves and mature in time to change to
chrysalids and emerge as butterflies in early summer. There is but one
brood a year and the species is widely distributed over southern
Canada and the Northern states. It extends south to Virginia and
Pennsylvania and west to Nebraska, Montana, and Washington.
=The Mountain Silver-spot=
_Argynnis atlantis_
If one were able to take a Silver-spot Fritillary and reduce its size
about one third he would have a wonderfully good imitation of the
present species. Except for the size, about the only difference in the
markings is found in the blackish border along the margins of the
Mountain Silver-spot which is not present in the other species. The
buff sub-marginal border line on the under surface of the wings
between the rows of silver spots is also wider in the mountain
species.
The distribution of this butterfly justifies its name. It is
preëminently a northern species, being especially abundant in the
White Mountains of New Hampshire and ranging northward far into Canada
and west through British America as far as the Mackenzie River. A pair
of these butterflies were captured by Merritt Carey on July 16, 1903,
on the summit of Mount Tha-on-tha, in the Nahanni Mountains, at an
altitude of 2,500 feet. The southern limit of its distribution
approximates the isotherm of forty-five degrees. It extends southward
in mountainous regions through New York and Pennsylvania and is found
in Michigan, Illinois, and Iowa. It also occurs in the Rocky Mountain
region of Colorado.
The various species of Argynnis show a remarkable uniformity in their
life-history. Like the others, this butterfly is single-brooded,
laying the eggs on or near violets late in summer, the eggs hatching
into larvae that take no food until the following spring. They then
feed upon the violet leaves, become mature, and change to chrysalids
in time for the butterflies to emerge in June in New Hampshire. These
butterflies remain upon the wing for several weeks. They usually
appear a week or two earlier than Aphrodite or Cybele in regions where
all three species are found. It is worth while for the collector to
take a hint from this fact and do his Silver-spot collecting early.
For after the other species appear it is not so easy to tell which is
Atlantis when the butterflies are on the wing. It is most likely to be
found in open places in the woods, apparently preferring such
situations to the broad expanse of fields and meadows.
=The White Mountain Fritillary=
_Argynnis montinus_
This is distinctly a mountain butterfly, known to be found only near
the top of Mount Washington and other neighboring parts of the White
Mountains. It generally occurs between the altitudes of four thousand
and fifty-five hundred feet. It is doubtless closely related to a
somewhat similar form found farther north and west, but its isolation
from them is complete. Apparently it is single-brooded and very little
is known of the early stages. The butterflies visit the flowers of
goldenrod and those of the alpine sand-wort which are abundant in the
sub-alpine home of this species.
This variety is interesting as a living souvenir of the day when New
England was buried beneath the ice-sheet.
=The Meadow Fritillary=
_Brenthis bellona_
The fact of variation is one of the most universal things in nature.
No two animals are exactly alike and every plant differs from every
other plant. That this is true of the structure of living things is
easily observed but it is not so well known, because not so easily
observed, that most species of animals differ also in the precise
phases of their growth. We know that the variation in form and color
has brought about the remarkable adaptations to surroundings which we
call mimicry and protective coloration. A little consideration will
make it evident that the variation of different individuals in periods
of growth must have led also to the adaptation of the life stages to
the conditions of the changing seasons. This is particularly true in
the great majority of insects which show remarkable adaptations in
their various broods to the seasonal conditions of the localities
where they live.
From this point of view the attractive little Meadow Fritillary is of
especial interest. We are indebted to the studies of S. H. Scudder for
our knowledge of the remarkable variations in its growth. These are so
complicated that in order to make plain the varying conditions it
seems necessary to separate the broods in a somewhat hypothetical
manner.
[Illustration:
THE SILVER-SPOT FRITILLARY
Upper and lower surfaces (_see page 125_)
THE GULF FRITILLARY
Lower Surface (_see page 115_)]
[Illustration:
THE GULF FRITILLARY (_see page 115_)
THE SILVER-BORDERED FRITILLARY
Upper and under surfaces (_see page 131_)
THE BALTIMORE CHECKER-SPOT
Upper and under surfaces (_see page 135_)]
We will begin with what we shall call Group A: The butterflies are on
the wing in May and early June. They have just come from the chrysalis
and continue living for three or four weeks before they deposit eggs,
this time being required in order that the eggs may develop in the
ovaries of the butterflies. These eggs hatch in about a week and the
caterpillars become full grown a month later. They then change to
chrysalids in which condition they remain another week, thus requiring
five or six weeks for the newly laid eggs to mature into butterflies.
Supposing the eggs were laid the first week in June, the butterflies
of this second brood would appear about the middle of July. The eggs
in the ovaries of some of these butterflies also require several weeks
before they are ready to be laid, so that it may be about the tenth of
August when this happens. These hatch and mature to chrysalids during
the next six weeks, the butterflies of this brood emerging about the
middle of September. These in turn lay eggs at once apparently, no
extended period being required for their development before they are
laid. The eggs hatch during the latter part of September and the young
caterpillars feed upon the violet leaves for two or three weeks,
moulting perhaps twice and becoming approximately half grown. They now
stop feeding and go into a lethargic condition in which they
hibernate. Then in spring they awaken and feed again upon the violet
leaves for a short time, becoming mature and changing to chrysalids
sufficiently early to emerge as butterflies late in May.
In this hypothetical group we have a fairly normal condition of a
three-brooded butterfly hibernating in the stage of the half-grown
larva and requiring some weeks for the development of the eggs in the
ovaries of the butterflies in the case of the first two broods but not
of the third.
In another group, which we may designate as B, the conditions may be
similar except that the butterflies lay their eggs very soon after
coming from the chrysalis in the case of all three broods. Obviously
there would be a tendency here for hastening the earliness of the
broods so that the hibernating caterpillars might either become larger
or might go into the hibernating condition earlier than those of
Group A.
In Group C, the variation takes place in the larvae rather than in the
butterflies. These may go on in the normal way up to the time the
caterpillars of the summer brood become half grown. Then they become
lethargic, ceasing to feed and to all appearances going into
hibernation. They remain in this condition until the following spring
when they come forth from their winter's sleep and feed upon the
violets in precisely the same way as the caterpillars of the third
brood of Groups A and B.
In Group D we have another interesting variation of the larvae. These
are the same as C up to the time of becoming lethargic, that is, the
larvae of the summer or second brood become lethargic at the same time
as those of Group C but instead of continuing in this condition until
the following spring they remain in lethargy only three or four weeks,
then they wake up (having apparently then changed their caterpillar
minds) and begin to feed, soon maturing and changing to chrysalids
from which butterflies emerge late in September or early in October.
The result is that these butterflies lay eggs so late that the cold
nights come on apace and the little caterpillars apparently take no
food at all but go into hibernation immediately. In consequence these
must eat for a longer period the following spring, so that the
butterflies into which they mature will be likely not to appear until
well along in June.
It is probable that even this rather elaborate statement does not do
justice to all the variations in the development of this little
butterfly. But perhaps enough has been said to help us to understand
something of the way in which such insects are able to adapt their
life habits to the conditions of their environment. It is easy to see
that if conditions should so change as to give any one of these groups
a decided advantage over the others, the tendency would be for the
other groups to disappear and for the group of favored habits to
survive.
The Meadow Fritillary is common in Canada and the Northern states east
of the Rocky Mountains. It is found especially in lowland meadows and
along the borders of swamps, the very situations chosen by the food
plants of the larva, the blue and the white violets. The butterflies
may be often seen sipping nectar from the various species of mint and
related plants found in such situations. It is commonly associated
with the Silver-bordered Fritillary, from which it is easily
distinguished because it has no silver spots upon its wings.
=The Silver-bordered Fritillary=
_Brenthis myrina_
This attractive little butterfly bears a close general resemblance to
the Meadow Fritillary, from which it differs chiefly by the continuous
row of silver spots along the border of the under side of both pairs
of wings. It is found in the same localities as the other and its
life-history is very similar.
The present species is widely distributed in North America, being
found as far west as the upper Mississippi Valley and the Rocky
Mountains, and southward as far as the Carolinas. In New England and
the Atlantic states it is one of the commonest of the smaller
butterflies.
Beginning with the butterflies which are seen in the fields and
meadows in September, the yearly cycle of this insect may be
summarized in this way: the eggs laid in September hatch in a few days
into tiny caterpillars, some of which become lethargic at once, while
others begin feeding upon the violet leaves and continue thus to feed
until they are about half grown. These then also become lethargic and
find shelter just above the soil surface where they remain until the
following spring. They then begin to feed again upon the violet leaves
and at about the same time the other caterpillars which became dormant
as soon as hatched, also waken and feed upon these leaves. Naturally
those which were half grown at the beginning of spring are likely to
mature and change to chrysalids two or three weeks earlier than those
which were so small at the beginning of the season. Consequently the
fresh butterflies will be found from late in May to the latter part of
June. Presumably those which first appeared have developed from the
larger caterpillars and the later ones from the smaller caterpillars.
The butterflies of this first brood of the season lay their eggs upon
the violet leaves, generally upon the upper surface of the blade, but
occasionally upon the stems or upon near-by grasses. These eggs hatch
in about a week into caterpillars that mature during the next three or
four weeks, coming forth as a second brood of butterflies late in July
or early in August. These in like manner lay their eggs and develop
into a third brood which matures as butterflies in September. These
lay eggs that hatch into the caterpillars which live through the
winter. There are thus three broods of butterflies during the year
and it is probable that there is the same remarkable variation in the
habits of the different broods that have been found in the ease of the
Meadow Fritillary.
_Synopsis of the Fritillaries_
_Gulf Fritillary_ (_Agraulis vanillae_). Expanse 2 3/4 inches. Apex of
each front wing produced into a distinct angle. Upper surface of all
wings reddish brown, marked with black spots and an interrupted black
border, the border on the hind wings enclosing round red-brown spots.
Under surface, so far as it shows when insect is at rest, nearly
covered with large silver-white spots. Found only in the more Southern
states.
_Variegated Fritillary_ (_Euptoieta claudia_). Expanse 2 1/2 inches.
Apex of each front wing produced into a distinct angle. Upper surface
of all wings fulvous brown, thickly marked with buff and brownish
black. A sub-marginal row of black dots on each of the wings, outside
of which is a row of buff crescents on the blackish border. Under
surface, as it shows when the butterfly is at rest, beautifully
marbled in creamy browns and deeper browns. No distinct silver spots
in either surface.
_Diana Fritillary_ (_Argynnis diana_). _Male._ Expanse 3 1/2 inches.
Apex of fore wings rounded. Upper surface of all wings, with a little
more than basal half, solid brownish black and the rest of the surface
orange-brown, marked with darker brown round spots and vein lines.
Under surface light buff, marked with black, with silver crescents and
spots on hind wings. _Female._ Expanse 4 inches. Upper surface of all
wings blackish with bluish or greenish iridescence, and marginal third
marked with blue spots and stripes. These are more prominent on the
hind wings. Under surface slaty brown with prominent silver crescents
on the hind wings.
_Idalia or Regal Fritillary_ (_Argynnis idalia_). _Male._ Expanse 3
inches. Front wings fulvous brown with black spots and markings. Hind
wings black except at base with a row of fulvous brown sub-marginal
spots and an inner row of whitish or bluish white spots. _Female._
Expanse 3 1/2 inches. Similar to male except for larger size and the
fact that the two rows of spots on the hind wings are yellowish brown.
_Great Spangled Fritillary_ (_Argynnis cybele_). Expanse 3 1/4 inches.
General color of wings fulvous brown with black markings on upper
surface and black and silver markings on under surface. The yellow
band between the rows of silver spots on hind wings is broad. There is
a distinct narrow fulvous stripe on the upper side of the hind wing
just inside the outer margin, and a similar stripe along the margin of
the front wing, more or less interrupted by the veins.
_Silver-spot Fritillary_ (_Argynnis aphrodite_). Expanse 3 inches.
Similar to the Great Spangled but a little smaller, and with the buff
yellow band between the rows of silver spots on the lower surface much
narrower and almost disappearing at the rear.
_Mountain Silver-spot_ (_Argynnis atlantis_). Expanse 2 1/4 inches.
Known by its smaller size and the black marginal border stripe on all
the wings, with no brown line dividing this stripe.
_Silver-bordered Fritillary_ (_Brenthis myrina_). Expanse 1 3/4
inches. Known by its small size and a marginal row of silver spots on
the under side of each of the wings, and with many other silver spots
scattered over the under surface of the hind wings.
_Meadow Fritillary_ (_Brenthis bellona_). Expanse 2 inches. Easily
known by the absence of silver spots on all the wings. The wings are
long in proportion to their width.
THE TRIBE OF THE CRESCENT-SPOTS
The members of this tribe have the following combinations of
characters: scaly antennae, with a short stout club some three times
as long as broad, and a pair of slender palpi in which the terminal
joint is only about half as long as the middle one. There may or may
not be a slight ridge running lengthwise of the naked part of the
antennal club.
Although more than fifty distinct species belonging to this tribe have
been found in North America, very few of these are distributed through
the eastern part. Only four are so abundant and widely distributed
that they need be treated of here.
=Baltimore Checker-spot=
_Euphydryas phaeton_
To the naturalist those islands in the seas which are remote from the
mainland have long been of especial interest. The life upon them is
likely to show the results of many generations of living under unique
conditions. The plants and animals are generally distinctive, many of
the species having characteristics which differentiate them markedly
from those upon the mainland. They show in a thousand ways the effect
of isolation and so are of especial value when one attempts to
determine the results of unusual conditions upon living things.
In a somewhat similar way the peat bogs or sphagnum swamps which occur
here and there over a large part of North America are of especial
interest, because in a way they are biological islands in which the
conditions of a long past age are preserved until the present. These
nearly always occur in a little valley surrounded on all sides by
hills. Here the water has collected originally into a pond or lake,
which has been gradually filling up through the growth of peat mosses
and a special set of other plants that develop in such situations. One
can still find many stages in the process. In some bogs the surface
will be practically covered, although the water beneath may still be
so abundant that the matted moss quakes as one walks over it.
Sometimes such bogs are really dangerous because the walker may drop
through to the water beneath. In most of the bogs, however, the little
lake is nearly filled but shows the surface over a small area.
The conditions in these peat bogs have changed little since
civilization began. They are relics of an earlier era which have come
down to us as types of conditions that once existed very generally.
The plant life is unique and consists almost entirely of forms which
are found practically nowhere else. There are comparatively few
animals living in these peat bogs and all of these are likely to be of
especial interest. Among the insects none is more remarkable than the
Baltimore Checker-spot butterfly which has several peculiarities that
differentiate it from the other members of the group. It seems to have
come down to us unchanged from a far remote past and to be living its
tranquil life to-day in precisely the same manner as during the time
when the mammoth and the mastodon were likely to invade its haunts.
The Baltimore is probably the most local in its distribution of any of
the butterflies found throughout Canada and the Northern states. It is
to be looked for only in peat bogs and swamps, and it has a remarkable
unity in its life-history whether it be found in northern Canada or as
far south as West Virginia. The butterfly itself is rather large,
measuring a little more than two inches across its expanded wings and
being colored with an unusual combination of fulvous and yellow upon a
black background. It is present as a rule only from about the first of
June to the middle of July. The eggs, in bunches of from one hundred
to four hundred, are laid upon the leaves of the plant commonly called
snake-head or turtle-head (_Chelone glabra_). They do not hatch for
nearly three weeks; then the little caterpillars emerge together and
usually each eats a little of the empty egg shell. They are then
likely to form a thin web over the under surface of the leaf beneath
which they remain as a small company feeding upon the succulent green
tissue. A little later they are likely to begin the construction of a
miniature nest by spinning a silken web over the young leaves at the
top of the plant. From this time on this silken nest serves as their
home, and they utilize it almost as effectively as do our familiar
American tent caterpillars the nest which they make in the forks of
the wild cherry tree. The Baltimore caterpillars often wander more or
less from their tent-like home but they generally come back to feed as
well as to moult. If the nest is injured by wind or rain, all the
caterpillars turn out to repair it and as the need for new food
supplies arises they also unite to enlarge the tent. This habit of
working together for the common good is very suggestive of the similar
habits of the American tent caterpillars. Doors for going in and out
are left in the tent during its construction.
The tent thus made is likely to be deserted after the first moult and
a new and larger one constructed on another part of the plant. Two or
perhaps three such nests may be made from the time the caterpillar
hatches until after the second moult. The last nest made is very
likely to be upon some neighboring bushy plant or at least to include
some branches of such a plant if the bulk of the nest is made upon
snake-head. For after the third moult the caterpillars stop feeding
and become more or less quiet, thus beginning a nine months' fast,
during which they are simply to wait until the return of spring. This
fast may be begun any time from the middle of August until early in
September, and even when brought indoors the caterpillars cannot be
induced to eat. It is evidently the way in which the species has
bridged over the winter during the thousands of generations of its
existence, and the instinct is so firmly fixed that it cannot be
changed. Even in West Virginia, where the caterpillars would have
plenty of time during the summer to mature as butterflies that would
bring forth another generation of caterpillars that might pass the
winter, the condition is the same as in the far northern regions.
So within the shelter of the silken nest these Baltimore caterpillars
remain from the middle of August until May. Then when the spring
sunshine has sufficiently warmed their cool retreats they come forth
and feed greedily upon the young leaves. They now soon make up for
lost time and complete their growth as caterpillars very quickly.
When full fed they wander about in all directions, each hunting its
own shelter before becoming a chrysalis. Having found a twig or branch
that suits their purpose each hangs downward and changes to a brownish
yellow chrysalis, more or less marked with black. It remains in this
condition for about a fortnight, when it comes forth as the Baltimore
butterfly which thus appears again about the first of June.
These butterflies seem to have some of the characteristics of their
unique surroundings. There are very few flowers in the peat bogs and
it is significant that the butterflies instead of flitting from flower
to flower, as do most of our familiar species, fly rather in a slow
and lazy fashion from leaf to leaf, lighting upon the foliage or
frequently upon the surface of the moss or ground. They seem lethargic
and have little of the animation which we usually associate with the
name butterfly.
In my mind the Baltimore is associated with the White Mountain
butterfly as a survivor of a former geologic period. The latter was
developed under colder conditions and now survives only on a few
isolated mountain peaks; but the former has survived wherever the peat
bog has held its sway during the long ages that the surrounding
landscape has been taking on its present-day condition. Many things in
the life of the Baltimore point to its primitive condition: the laying
of the eggs in loose clusters, the long lethargy of the caterpillars,
the limited flight of the butterflies--all indicate a creature with
habits firmly fixed by long ages of development in a definite
environment.
No collector should feel sure that the Baltimore is not to be one of
his trophies until he has visited in June every peat bog or sphagnum
swamp in his locality. One may search years without finding it, and
then come across a dozen in a single day. I well remember the interest
with which I first found this species on the margin of a great swamp
in Michigan when I was eager for every new butterfly to add to my
collection. I had never seen it alive before and the thrill with which
the first specimen was captured can be realized only by those
remembering similar experiences.
=Harris's Checker-spot=
_Cinclidia harrisii_
This little butterfly so closely resembles the Pearl Crescent and the
Silver Crescent that on the wing it is easily mistaken for them. It
really looks more like them than it does the Baltimore Checker-spot,
which is considerably larger and darker colored than the present
species. This is essentially a northern form occurring only in a
narrow strip of country east of Minnesota and Wisconsin, running on
the north through southern Canada and on the south through Michigan,
New York, and Massachusetts.
This insect is one of the best-known botanists among all the
butterflies. In the very difficult group of asters which has caused
endless confusion to human botanists these insects seem always able to
select the one species--_Aster umbellatus_. It has been repeatedly
found that the caterpillars would starve rather than eat the leaves of
other kinds of asters, and so far as known they have never been found
feeding outdoors upon any other.
These butterflies appear along roadsides and in open fields about the
middle of June. They are often very abundant and are much more
generally distributed than the Baltimore Checker-spot. A few weeks
later the females lay their eggs upon the aster leaves, the eggs being
deposited in clusters of twenty or more on the under side of the leaf.
Early in July the little caterpillars come forth and remain together
in colonies as they feed upon the green tissues of the leaves. Each is
able to spin a silken thread so that wherever they go they weave a web
and they soon protect themselves with a slight silken shelter, which
is suggestive of the nests made by the Baltimore caterpillar. They
continue to live in this manner for several weeks in July and August,
growing rather gradually and becoming approximately half grown before
the frosts of autumn. Unlike the Baltimore caterpillars they now
desert their nests and find shelter at or near the surface of the
ground. Here they hibernate, to come forth the following spring and
feed again upon the new growth of the aster plants, often doing
considerable damage by denuding the young shoots of their leaves. They
become full grown in time to change to chrysalids so that the
butterflies may emerge in June.
=The Silver Crescent=
_Charidryas nycteis_
While this species has not the broad distribution for which the Pearl
Crescent is notable it occurs over a large part of the United States.
Its distribution is bounded broadly by a line running from southern
Canada north of Maine to a point in southern Canada north of Montana,
whence it runs south through Wyoming and Utah to the corner of
Arizona, and thence east through New Mexico and Texas to Ohio and West
Virginia, extending south near the coast to North Carolina. It thus
includes a broad belt of territory occupying fully one half of the
area of the United States.
Throughout this vast area the Silver Crescent is often a purely local
species, occurring abundantly during its brief season in some
favorable locality but seldom being seen in other places near by. In
the north it is single-brooded, the butterflies appearing on the wing
during June and commonly disappearing early in July. Late in June the
females lay their eggs in clusters of a hundred or less on the under
surface of the leaves of various composite plants, notably sunflowers,
asters, and a common species of Actinomeris. A week or more later
these hatch into little caterpillars that feed together in colonies
upon the green tissues of the leaf, taking only the succulent
parenchyma and leaving the network of veins. As one leaf is thus
denuded they migrate to another, in this way passing from leaf to leaf
for several weeks in summer. They continue to feed until about half
grown when they desert the food plant and find shelter at the soil
surface. Here they become lethargic and hibernate until the following
spring. They then arouse again and feed upon the tender leaves of the
new growth, continuing to eat and grow for a few weeks before they
become mature as caterpillars and change to chrysalids. A little later
the chrysalids disclose the butterflies which as already indicated
appear in June.
In more southern regions the life-story of the species is not so
simple. There is at least a partial second brood and it is probable
that in many localities the species is both single-brooded and
double-brooded. In such a case some of the caterpillars go into
hibernation probably about midsummer, remaining quiescent through the
later weeks of summer and all the weeks of fall and winter, while
others would mature to chrysalids and butterflies in summer, and the
butterflies would lay eggs for a second brood of larvae which would
hibernate when partially grown. There are opportunities for careful
observers to do good work upon the life-history of this species in
many parts of its range.
=The Pearl Crescent=
_Phyciodes tharos_
Some years ago Mr. Samuel H. Scudder, the most notable student of New
England butterflies, wrote a delightful essay with the title
"Butterflies as Botanists." From his long experience in rearing the
eggs of these insects he concluded that the egg-laying females know in
a most remarkable way the precise kinds of leaves upon which to
oviposit. He educed many illustrations in proof of the fact and quoted
a remark of Asa Gray, the most eminent of American botanists, that is
worth repeating. At that time Scudder had reason to believe that the
Pearl Crescent laid its eggs exclusively upon the New England aster.
Now the asters as a group have been a source of much trouble to the
botanists who have attempted to classify them as to species and
variety. The various forms are so similar to one another that
different authorities have not agreed as to the limitations of the
species. So when Gray was told that this little butterfly was able
always to distinguish and select for her egg-laying a single species
of this vexing tribe he replied: "If your butterfly selects only that,
it is a better botanist than most of us."
While later observers have found that this beautiful little insect is
not so exclusive in its choice of a food plant as was formerly
believed, it serves to illustrate the fact that a large proportion of
the caterpillars of this group have a very narrow range of food
plants. In nearly every case where the food is thus restricted the
insect feeds only upon species which are closely related to one
another, generally falling within a single genus according to the
classification of the botanists.
There has been much discussion in regard to the way in which the
mother butterfly knows the particular species which she chooses for
oviposition. Experiments apparently have shown that she is not
dependent upon the sense of sight but rather upon the sense of smell,
which as is well known is much more highly developed in insects than
in the higher animals. I suppose it is not very strange that a
creature which has fed from infancy upon leaves with a certain taste
and odor should in its later life respond only to that particular odor
and should neglect all others. In a way the butterfly itself is a
product of the plant and it probably is not necessary to assume that
each butterfly differentiates the odors of all kinds of plants but
only that she responds to the fragrance of the one with which she has
been particularly associated.
[Illustration: _From a drawing by Mary E. Walker_ _See page 153_
THE HOP MERCHANT
Caterpillar, chrysalis, and butterflies. (Reduced)]
[Illustration: Mourning-Cloak
_See pages 112, 171_]
[Illustration: The Viceroy visiting wild carrot flowers
_See page 195_
EXAMPLES OF FOUR-FOOTED BUTTERFLIES SHOWING USE OF THE FOUR LEGS
(Photographed from life)]
This idea may suggest to various observers an interesting point of
view. When you see a butterfly flying leisurely from plant to plant
and alighting upon the leaves rather than the blossom, you may be
pretty sure that she is bent upon egg-laying. Now watch her to see if
she goes at once to the particular kind of leaves she finally selects
or does she stop momentarily upon neighboring plants, apparently
trying to find the one from which the fragrance emanates until at last
she reaches it. Such observations have only rarely been recorded and
if carefully made, notes being taken on the spot, they would have
decided scientific value.
_Abundance and Distribution_
Few butterflies are more abundant or more widely distributed
throughout North America than the beautiful little Pearl Crescent. It
occurs over practically the whole of the United States and Canada and
is found from early in spring until late in autumn. It is a rather
small species with a wing expanse of only about an inch and a quarter,
the upper surface of the wings being that tone of reddish brown called
fulvous, more or less marked with black wavy lines and dots. The under
surface is similar in color, with a small silver crescent near the
outer margin of each hind wing.
These butterflies are not very active creatures, although they are
commonly found in meadows and pastures along brooks and by the borders
of open woods. Instead of laying their eggs singly as do so many of
the more active butterflies, they lay them in clusters, often of a
hundred or more, one layer of eggs being placed above the other upon
the aster leaf. In at least one case observed, the caterpillars hatch
from the layer farthest away from the leaf surface before those of the
layer next the leaf surface emerge. This is an interesting provision,
for were the latter to come out first they would be likely to
disarrange the unhatched eggs. The caterpillars appear about a week
after the eggs are laid and remain together in crowded colonies that
feed upon the upper surface of the aster leaf. At first they eat only
the green tissue, leaving the bare veins, although they are not
careful to denude the entire surface of the leaf as so many other
caterpillars do. As one leaf is exhausted they pass to another near
by, continuing thus to feed in companies for a few weeks. Their
general color is blackish, although the black is relieved with yellow
dots along the back and a band of a similar color on each side. Unlike
the larger social caterpillars of the Mourning Cloak and other
butterflies these larvae do not spin any threads as they crawl from
place to place, so there is absolutely no nest made upon the aster
leaf. This may possibly be correlated with the fact that these
caterpillars are sluggish creatures and when disturbed drop quickly to
the soil beneath.
When the caterpillars are full grown, they fall or crawl to the ground
and scatter more or less in search of shelter. Each attaches itself to
any protection it may have found and changes to a grayish or brownish
chrysalis more or less angular. It remains in this condition for a
period that varies greatly with the weather conditions, averaging
about two weeks.
There are two distinct forms of these butterflies which vary so
greatly that they were once considered separate species. They are now
known, however, to be only seasonal variations. In New England two
broods of the insect occur, one in spring, the other in summer. The
spring form is called technically _Phyciodes tharos tharos_. In this
form the under surface of the hind wings is very distinctly marked
with blackish spots. The summer form is called _Phyciodes tharos
morpheus_. It is noticeably larger than the spring form and it has
very few markings on the under surface of the hind wings.
_The Yearly History_
As it occurs in New England the yearly history of this little
butterfly runs something like this. The spring form of the adult
appears in May and lays eggs upon the aster leaves. These eggs hatch
into caterpillars that feed upon the aster leaves for several weeks
and then change to chrysalids, remaining in the latter stage ten days
or two weeks. They then come from the chrysalids in the form of the
summer butterflies which begin to appear about the middle of July and
continue to emerge for at least a month. These lay eggs upon the aster
leaves again and the little caterpillars that hatch from them feed for
a few weeks or until about the last of September. They are then only
partially grown, but they make no attempt to complete their
transformation at this time. Instead they drop to the ground and go
into hibernation, remaining in this condition until early the
following spring. They then begin feeding again and complete their
development in time to emerge as the spring form of the butterfly in
May.
Some very interesting experiments by William H. Edwards have shown
that the smaller, darker spring form of the butterfly is due to cold.
He placed upon ice chrysalids that would normally produce the summer
form and found that the specimens so treated produced the spring form.
This butterfly is one of the best known examples of the variation in
the yearly cycle due to differences in latitude. This is readily shown
by a brief summary of its life-history, from north to south.
In the far northern climate of Labrador there is but one brood a year
and the butterflies belong to what I have been calling the spring
form. The butterflies appear on the wing in early summer, lay their
eggs upon the aster leaves, and die. The eggs hatch into caterpillars
that feed for several weeks, then become dormant and remain in such
shelters as they can find until the following spring. They then change
to chrysalids to emerge as butterflies a little later. There is thus
but one brood a year and the only form of the butterfly is the small,
darker colored variety.
As far south as southern Canada there is a slight variation in this
yearly cycle. The spring form of the butterflies appears in May and
lays eggs. The eggs hatch into caterpillars; part of these
caterpillars mature within a few weeks, change to chrysalids, and come
out in July or August as the larger summer form of the butterfly,
which in turn lays eggs for the caterpillars that are to winter over
in a dormant condition and mature the following season. But the
significant fact is that not all of the caterpillars which thus have
hatched in spring go through this cycle. Part of them become dormant
when partially grown and continue dormant through summer, autumn, and
winter, just as they did in Labrador. Then in spring they develop into
the spring form of the butterfly, along with the caterpillars that
have hatched from the eggs laid in summer. There is thus what is
called an overlapping of the broods.
Farther south, in southern New England, the life-history is more
definitely two-brooded each year, as already described in an earlier
paragraph. Still farther south, in the region of the Virginias, it is
definitely three-brooded, there being at least two summer broods
during the year. How is it that the instinct to become lethargic lies
dormant in the summer broods of caterpillars and shows itself only in
the autumn brood? Is it perhaps due to a reaction to the colder nights
of the later season? If so, possibly one could get interesting light
upon the subject by experimenting with placing the summer caterpillars
temporarily in an ice chest.
_Synopsis of the Crescent-spots_
_Baltimore Checker-spot_ (_Euphydryas phaeton_ or _Melitaea phaeton_).
Expanse 1 3/4 inches. General color purplish black with the upper
surface marked thus: a marginal row of red-brown spots between the
veins; two rows of creamy yellow spots inside of the row just
mentioned; two or three small red and two or three small white spots
near front border of each front wing. Under surface checkered in
red-brown and creamy yellow on a blackish background.
_Harris's Checker-spot_ (_Cinclidia harrisii_ or _Melitaea harrisii_).
Expanse 1 3/4 inches. This species bears a close general resemblance
to the Silver Crescent. It may be distinguished by the fact that the
middle joint of each palpus is of uniform size from end to end instead
of tapering toward its outer end. The tibial joint of the first pair
of legs of the male butterfly is very thick. The upper wing surface is
so marked with black that the tawny red coloring shows only in the
middle.
_Silver Crescent_ (_Charidryas nycteis_, _Melitaea nycteis_ or
_Phyciodes nycteis_). Expanse 1 3/4 inches. This species may be known
from Harris's Checker-spot by the fact that the middle joint of each
palpus tapers from the middle to the tip and that the tibia of each
front leg in the male is slender rather than stout. On the lower
surface of the wings there is a narrow yellowish marginal line.
_Pearl Crescent_ (_Phyciodes tharos_ or _Melitaea tharos_). Expanse
1 1/2 inches. General color much lighter than either of the preceding.
Terminal joint of each palpus less than a third as long as the middle
joint.
THE TRIBE OF THE ANGLE-WINGS
The special characteristic that distinguishes the members of this
important group from the other Nymphs is the fact that on that portion
of the club of each antenna which has not hairs there are three
longitudinal ridges. The tribe includes a large number of our most
familiar butterflies. Nearly all of them are rather large, with bright
attractive colors. They fly freely along roadsides and in orchards,
fields, and meadows so they are commonly seen by every one.
=The Violet-tip=
_Polygonia interrogationis_
The Violet-tip is one of the largest of the Angle-wings, as well as
one of the most beautiful of all our species. It has a wonderful
violet iridescence which is especially marked on the projecting tip of
the hind wing. On fresh specimens, however, it may be seen practically
all over both surfaces of the wings and in bright sunlight gives them
a sheen of remarkable beauty. The expanded wings measure nearly two
and a half inches, the upper surface being marked with dark brown
upon a ground of orange-brown. The under surface has a bark-like
effect in brownish gray brought about by rather indefinite markings of
varying tone. The most characteristic feature is a distinct silver
semicolon on the middle of the under surface of each hind wing. This
marking closely resembles the Greek interrogation point and so the
species was given the specific name _interrogationis_ by Fabricius
early in the history of science. It has since often been called the
interrogation butterfly as a translation of its Latin name, but in as
much as the marking on the wings is not at all like the English
interrogation point, this has led to considerable confusion and people
have considered it a misnomer. It has also been called the Semicolon
butterfly which is correct enough so far as this most characteristic
feature is concerned; but it leads to confusion in connection with the
Latin name. The recent practice seems the better, which is to call it
the Violet-tip butterfly.
_Life-history_
The life-history of this butterfly is much like that of the related
species. Briefly summarized, this is its story:
The adult butterflies, more or less worn and faded from their long
hibernation, appear in fields and pastures in May. They fly for
several weeks sipping nectar from many kinds of spring flowers. The
females search for the leaves of the elm, hop, nettle, false nettle,
and perhaps other related plants on which they deposit their ribbed
eggs either singly or in small groups, it often happening that one egg
will be laid directly on top of another. About a week later the eggs
hatch into small spinose caterpillars which begin feeding upon the
leaves near by. They continue to feed and grow rather rapidly until
they become full size. Each then fastens a bit of pink silk to the
stem of the plant or some other support, in which it entangles its
hind legs and hangs downward to become a chrysalis which is remarkable
for its numerous protuberances and the beautiful silvery and golden
spots along the middle of the back. Within these chrysalids the change
from larva to butterfly takes place, usually in less than two weeks,
so that this new brood of adults appears on the wing early in July.
Eggs are laid by these for a second brood of caterpillars that feed
upon the host plants in the same way as the others, and mature as
butterflies late in August or early in September. These butterflies
visit the fall flowers and suck the juices of fallen fruits, until the
cold weather of autumn warns them to seek shelter for the winter. They
now find crevices within the bark of trees or places in hollow logs or
stone piles or other similar situations, where they close their wings
together, so that only the bark-like under surface shows, and remain
quiet for long periods. They hibernate in this way, coming forth again
the following season to start the cycle for the new year.
In regions where hops are grown commercially the chrysalids of these
butterflies are often called "hop merchants." There is a quaint fancy
that the price of the crop varies with the lustre of the golden spots
upon the chrysalids. When these stand out conspicuously, according to
this fancy, the hops are to sell high--bringing much gold to the
owners. When these are inconspicuous the hops are to sell at a low
price, with a corresponding diminution in the returns. But this fancy
does not apply at all to the chrysalids when they are nearly ready to
disclose the butterfly, for at this time they lose their metallic
lustre.
=The Hop Merchant or Comma=
_Polygonia comma_
There are two species of butterflies which commonly lay their eggs
upon the hop and which resemble each other so closely in their earlier
stages that they are frequently confused by ordinary observers. One is
the Violet-tip or Semicolon and the other is the one which has long
been called the Comma. The chrysalids of both are marked in silver and
gold and the variation in the golden lustre has led hop growers to
deduce from them the probable price of hops. On this account the
chrysalids are commonly called Hop Merchants and the name has been
transferred to the butterflies themselves. (_See plate, page 144._)
The Comma is easily distinguished by the conspicuous silver mark in
the middle of the under side of each hind wing. This bears a striking
resemblance to a comma, hence the name. The butterflies are somewhat
smaller than the Violet-tips and show to a remarkable degree the
angularity in the borders of the wings. The under side is cleverly
marked in imitation of the bark of trees, which is doubtless of much
benefit to the species in eluding observation during the long months
from October until April, when the butterflies are hibernating in such
concealed shelter as each happens to find. The crevices beneath loose
bark, the openings in fallen logs and hollow trees, the interspaces in
stone piles, as well as the interior of buildings, all serve this
purpose.
Like the other over-wintering butterflies, the specimens that come
forth in spring are commonly faded and more or less frayed from their
long wait since bursting forth from the chrysalis. They may often be
seen sunning themselves on bright days in April and May, resting upon
stones or logs in sheltered spots with their wings fully expanded to
receive the greatest benefit from the rays of sunshine.
[Illustration: Eggs laid in string-like clusters on the under
side of leaf. Magnified. (From Holland)]
When spring has sufficiently advanced for the leaves of the elm and
the hop to be fairly well developed, the mother butterflies lay their
eggs in a curious and characteristic fashion. Under a lens these eggs
look like tiny barrels with vertical ribs. They are deposited in
columns, the egg first extruded being attached to the leaf, generally
the under surface, and those which follow are placed one upon the
other sometimes to the number of six or eight, the group thus making a
miniature column. Now if the egg which was first laid should hatch
before the others, when the little caterpillar came out it would be
very likely to cause the others to fall off and when they hatched they
would find themselves in what would be to them an impenetrable forest
of weeds and grasses from which there would be small chance to escape
to reach the elm or hop leaves. To avoid this calamity we find an
interesting adaptation. The egg at the end of the column hatches
first, although it was necessarily the one laid last. The tiny
caterpillar eats its way out of the shell and crawls over the other
eggs to the leaf. Then the others hatch in succession.
The eggs thus deposited by the hibernating butterflies are likely to
be laid late in May or even early in June. They hatch into
caterpillars less than a week later and these caterpillars feed for
about a month, when they change to the characteristic chrysalids in
which they commonly remain for a week or ten days. They then emerge as
the summer brood of butterflies, most of them in New England appearing
during July. These remain upon the wing for several weeks, the females
laying their eggs upon the elm and hop leaves. These in turn soon
hatch into caterpillars that change to chrysalids in August and emerge
as butterflies late that month or during September. This autumn brood
of butterflies is quite abundant for a time but soon seeks the
seclusion of winter quarters to remain until the following April.
There are thus two distinct broods during the year in the Northern
states while as far south as West Virginia there are likely to be
three broods.
These caterpillars at first simply eat small holes in the green
substance of the leaf, but as they become larger each takes up its
abode on the under surface of a single leaf and makes a sheltered tent
in somewhat the same fashion that the Painted Lady does upon the
nettle leaf. The caterpillar eats out more or less of the base of the
blade on each side of the midrib, thus weakening the edges so that
they can be fastened in a tent-like manner by silken threads. This
serves as a resting place from which it sallies forth to feed,
commonly only toward the tip of the leaf. As a result it often eats
itself out of house and home and has to crawl to another leaf and
construct a new shelter.
While the Comma is generally spoken of as a characteristic northern
species it has a very wide range, being found from New England to
Texas and from the Northwestern states to the Carolinas. It is one of
those species which have two distinct forms of coloring. The winter
form has been given the variety name _harrisii_. The butterflies of
this brood are decidedly lighter in color than those of the summer
brood to which the variety name _dryas_ has been given. The latter was
originally described as a distinct species by W. H. Edwards.
_The Change to the Chrysalis_
The manner in which a larva changes to a chrysalis is second in
interest only to that in which a chrysalis changes to a butterfly.
There are not a great many careful descriptions by competent observers
of this process in print. One of the best of these is that by W. H.
Edwards in his splendid work on "The Butterflies of North America," in
which he describes the transformation of the Comma caterpillar. It is
as follows:
"When about to transform, the caterpillar selects a convenient place
on the under side of a projecting rock, or of a fence rail, or of a
weather board of the house, or the midrib of a hop leaf, and having
spun a little button of pale red silk fixes the hooks of its hind legs
therein and hangs suspended, head downward, in the shape of a fishhook
and remains immovable for the space of twenty-four hours, no change
being perceptible except in the color of the skin, which becomes
partly transparent and loses its dark color owing to its gradual
parting from the chrysalis within. Suddenly, and to a looker-on
without any premonitory symptom, a rent takes place in the skin at the
back of the head, just wide enough to allow the passage of the
chrysalis, the head of which at once emerges. By a rapid contraction
and expansion of the folds of the abdomen the larva draws the skin
upward, successively discovering the parts of the fully formed
chrysalid until at last, and in scarcely more than one minute of time,
the entire skin is gathered about the hind feet. It now bends itself
violently to disengage the end of the chrysalis, which is long,
pointed, and hard, furnished with several little hooks, meanwhile
retaining its hold of the skin by the folds of its abdomen until after
a severe effort, convulsively reaching out and feeling in all
directions for the object of its search, it touches the button of silk
and at once grasps it with its hooks and fixes them in it securely.
Then by a twisting motion it manages to disengage the loose skin which
falls to the ground and the chrysalis rests. The whole process is most
interesting to witness and excites renewed wonder with every
repetition at the ingenuity of the means employed and the delicacy of
the instinct displayed. How to strip off the skin and much more the
legs by which the creature is suspended without losing its hold, and
at the same time to securely fasten the chrysalis, is a problem that
would seem impossible to solve; and yet this little insect
accomplishes it unerringly when to fail would be certain destruction.
And not this species only, but the larvae of all butterflies which
form suspended chrysalids, embracing the whole of the great family of
Nymphalidae, that is, a large proportion of all the existing species
of butterflies, undergo a similar transformation.
"The chrysalis is now green in color, soft and indefensible,
susceptible to the slightest injury, and for a few moments the several
parts of the future butterfly may be seen and readily separated; the
wings folded close and enveloping the thorax, the antennae, and
proboscis stretched at length along the back; but very speedily a
complete casing is formed by the exuding from parts of the body of a
viscous fluid, which binds together the tender parts and covers the
whole with a coating like varnish. This soon hardens and the chrysalis
is ready to take its chance against injury."
=The Gray Comma=
_Polygonia progne_
This butterfly is rather darker colored, especially on its under side,
than the one last discussed. The silver marking takes on a little more
definitely the form of an L than a comma, and the under surface of the
wings is darkened by many blackish threadlike lines running across the
veins. When at rest with wings closed these butterflies are very
easily overlooked.
Except for a difference in the food plants of the caterpillar, the
life-history of the Gray Comma is very similar to that of the other
Comma. The butterflies hibernate, and in spring lay eggs singly on the
leaves of currants, gooseberries, and related plants. The eggs soon
hatch into caterpillars that feed upon these leaves but do not make
any suggestion of a nest. They grow slowly and change into angular
chrysalids which disclose the summer brood of butterflies in July.
These lay eggs for another brood of caterpillars which mature into
butterflies in August and September. These generally go into
hibernation before the middle of October, sometimes choosing simply
the under side of a branch where their dark coloring, so near like
that of the bark, is likely to cause them to be overlooked by their
numerous enemies.
=The Green Comma=
_Polygonia faunus_
The Angle-wings exhibit interesting variations in the geographical
distribution of the species. Some are characteristic members of the
Canadian fauna, others of the Alleghanian fauna. Some of those which
are characteristic of the former are scattered south well into the
latter, but the Green Comma is distinctively a northern species--being
found abundantly in the great regions traversed by the trappers of the
Hudson Bay Company and occurring south as far as northern New England,
being very rare as far south as northern Massachusetts. It is abundant
on the higher slopes of the White Mountains.
As one might expect from the short seasons of the far northern regions
in which this butterfly lives, there is only one brood each year. In
consequence the adult butterflies live a long time. Coming from the
chrysalis generally the first weeks in August, they remain upon the
wing a month or more before they go into hibernation. They come from
their winter quarters in May and commonly continue alive until late in
June. Thus it is evident that many of these butterflies must live at
least ten months as adults, an extraordinary longevity for one of
these frail creatures.
The caterpillars are known to feed upon the foliage of several kinds
of plants. These include alder, currant, gooseberry, willow, and black
birch, the last two named apparently being those most often chosen.
Mr. S. H. Scudder called attention to the fact that these butterflies
are able to make a slight clicking noise as they start into flight.
He described his experience in these words:
"Starting up a pair just at my feet on the Mt. Washington carriage
road one day, I stopped abruptly to see whether they would settle
again. After flying a few yards away to escape the cause of their
disturbance, one turned back and dashed straight at my face, turning
only when within three or four inches of my nose, and then suddenly
whisked off with a distinct click as it did so, snapping its fingers,
as it were, in my very face. There was no sort of doubt about this
click, though if it had not been made so close at hand it would
probably not have been heard. But other butterflies in the tropics
have long been known to emit sounds like this, which can be heard at a
considerable distance; others, including some of our own butterflies,
are known to produce a rustling sound by the rubbing of one wing upon
another; and movements of one sort and another have been so often
observed, as of the opposite rubbing of the erect wings in most
Lycaenids, and the tremulous agitation of the wings in many different
sorts when excited, as to leave little doubt that sounds made by
themselves and for the advantage of warning their brethren play a not
unimportant part in the lives of butterflies."
[Illustration: _See page 233_
MONARCH BUTTERFLY IN RESTING POSITION]
[Illustration: _Photograph by Miss J. Brooks_
_See pages 17, 232_
FLASHLIGHT PHOTOGRAPH OF MONARCH OR MILKWEED BUTTERFLIES
IN MIGRATION]
[Illustration: THREE ANGLE-WINGS: UPPER SURFACE
The American Tortoise-shell (_see page 182_)
The Red Admiral (_see page 160_)
The Violet-tip (_see page 150_)]
[Illustration: THREE-ANGLE WINGS: LOWER SURFACE
The American Tortoise-shell (_see page 182_)
The Red Admiral (_see page 160_)
The Violet-tip (_see page 150_)]
[Illustration: _From a drawing by W. I. Beecroft_
_See page 163_
THE PAINTED BEAUTY
Caterpillar, chrysalis, and butterfly]
=The Red Admiral or Nettle Butterfly=
_Vanessa atalanta_
Among the weedy plants which have been intimately associated with
mankind ever since his slow upward progress in civilization began, the
nettle has probably played almost as important a part as the thistle.
While it lacks the winged seeds of the latter it is even more
effectually protected from the attacks of vertebrate enemies on
account of its irritating hairs. At any rate, nettles of various kind
are widely distributed over the earth's surface, and consequently it
is not surprising that the Nettle Butterfly or Red Admiral should be
almost as cosmopolitan as the Thistle butterfly. The two species are
closely related in structure and habits and the life-history of the
one is very similar to that of the other.
About the middle of May one may see in open fields and along sunny
highways these Red Admirals flitting from flower to flower, or
stopping occasionally upon green leaves in search of opportunities to
lay their eggs. Should you observe them closely you might notice that
some of them seemed frayed and worn while others seemed perfectly
bright and fresh.
_The Life-story_
Late in May and early in June these butterflies deposit their eggs
upon the leaves of the nettles. As a rule only one or a few eggs are
laid on a leaf, but when the butterflies are abundant many leaves upon
the plant may become infested. About a week later the egg hatches into
a larva, which is likely to eat more or less of the empty shell before
crawling up the stem of the plant to the unfolding buds at the top.
Here it makes its first nest by webbing together the still closed
upper surface of a leaf not yet unfolded. It is thus able to furnish
itself with protection from weather and enemies, as well as an
abundant supply of succulent food. It remains in this first home about
a week, then it casts its skin, still within its protection, and stays
until it has recovered after the process. It now migrates to another
larger, expanded leaf where it very cleverly proceeds to construct its
second nest. In order to do this it weakens the midrib at the base of
the leaf by biting nearly through it. Then it cuts a hole in the blade
of the leaf at the base in such a way that the margins are made to
droop, so that they can be fastened together with silk to form a
little tent. We thus have a tent-like nest hanging down from the stem
of the leaf on the under side of which the caterpillar will find
shelter, while near at hand is the green tissue of the inner surface
of the leaf waiting to be eaten. This improvised tent serves as the
home during this second stage of the caterpillar. Here also the second
moult commonly takes place, after which the caterpillar migrates to a
new leaf and constructs its third nest. The rest of the story of the
caterpillar's life consists of similar chapters. After each moult a
new tent is formed and even the chrysalis is often hung within the
last one.
The eggs which were laid late in May develop into butterflies during
July. These in turn lay eggs for the second brood of caterpillars most
of which develop into butterflies late in August or early in
September, but some of which apparently remain in the chrysalis stage
unchanged throughout the winter, and mature as butterflies about the
middle of the following May. This is the explanation of the fact
mentioned at the beginning of this discussion that one can find late
in spring and early in summer some butterflies which seem worn and
frayed while others seem perfectly fresh. They are all the progeny of
the midsummer brood of the previous summer, but some of them have been
living as full-grown butterflies through eight long months of
tempestuous weather, while others have just been disclosed from the
protecting walls of the chrysalis.
The world-wide distribution of this butterfly is shown in the
statement that it occurs throughout Europe, and in North America from
Newfoundland to Cuba and Guatemala. It is a safe guess that it is
found in practically all localities where nettles grow.
It is not alone the association between a butterfly caterpillar and
its host plant which has been brought about during the long ages
through which one generation has been succeeding another, but there
have been also many developments of similar associations between the
caterpillars and their parasitic enemies. The Red Admiral is a good
example of such a development. During its long growth as a species it
has been exposed to attack by vast numbers of tiny foes which live at
the expense of other insects. Several of these foes have found in the
bodies of the caterpillars good opportunities for growth, so that now
the Red Admiral, as a species, has to reckon with many enemies among
these tiny parasites. The interaction between caterpillar host and
uninvited parasitic guest has much to do with the great irregularity
in the numbers of the butterflies. It is simply another example of
that complicated struggle for existence, by means of which nature
keeps ever a fairly even balance of her myriad forces.
=The Painted Beauty=
_Vanessa huntera_
One of the most interesting phases of the study of butterflies is to
learn how often they take advantage in their life-history of any
peculiarity of the food plant which has a protective value. The
Painted Beauty is an excellent illustration of this. The caterpillar
feeds upon the leaves of the common Everlasting or Gnaphalium. This is
an abundant and widely distributed plant, found along roadsides and in
fields and pastures. It is notable for the woolly covering on stems,
leaves, and flowers--this dry, hairy surface being so evident that the
flowers will apparently continue in blossom when they have dried,
hence its common name Everlasting or, as the French call a similar
flower, Immortelle. (_See plate, page 161._)
The utilization of the hairs upon the leaves is begun by the mother
butterfly when she lays her egg upon the upper surface, pushing it
down among the hairs so that it is almost concealed. Should you be
fortunate enough to find one of these eggs you would see that it is a
small, yellowish green object, looking like a tiny barrel with several
vertical ribs upon its surface. A few days after the egg is laid it
hatches into a minute caterpillar that begins eating off the hairs
where they are attached to the leaf, in such a way that it soon has a
free space beneath a bunch of these hairs which it has more or less
matted together by means of silken thread. The little caterpillar has
thus provided for itself a protecting nest that effectually conceals
it from birds or other enemies. It now begins feeding upon the
succulent surface of the rather thick leaf, where it has removed the
hairs. After several days of such feeding it moults, still under the
shelter of its hairy covering. This process of moulting and feeding
continues for two or three weeks, the caterpillar occasionally making
a new covering as needed for its food supply.
The later nests are likely to be made by folding two or three leaves
together, binding them with silken thread. The caterpillar in doing
this takes advantage of the fact that the terminal leaves are vertical
before they have spread out, so that it is a comparatively simple
matter to make a little house by binding their edges together with
silken threads. The larva feeds upon the inner walls of the house it
thus constructs, and as it becomes larger the buds and blossoms are
also utilized for food.
When the caterpillar is full grown it thus finds itself fairly well
concealed within a very substantial sort of a home. Many of them have
the apparent good sense to realize that this is as safe a place as
they are likely to find for shelter during the period of the
chrysalis. So the caterpillar makes the nest especially secure near
the centre of what might be called the ceiling and in this web it
entangles its hind legs and hangs downward, preparatory to changing to
the chrysalis. A few hours later the skin splits apart and is wriggled
off, leaving the chrysalis hanging in place of the caterpillar. About
a fortnight later the butterfly emerges and crawls at once to the
outside of the nest, where it rests quietly while its wings expand and
its tissues harden. Then it flies away in search of the nectar of
thistles and many other flowers which it visits freely.
This Painted Beauty is a wonderful example of harmonious coloring. The
general tone of the upper surface of the wings is fulvous, with some
distinct white markings on a blackish background at the outer angles
of the front pair. There is also more or less blackish shading on the
base and margin of all the wings with an indistinct row of about four
dots, more or less run together, near the margin of the hind wing. The
under surface of the wings is even more beautiful than the upper, and
furnishes a striking example of flower-picturing. There is a little
fulvous background near the middle of the front wings, but the rest of
the surface is spotted and striped with blotches and circles of gray
and brown in a most intricate design. On each front wing near the
outer angle are three indistinct eye-spots in a row, and on the outer
half of each hind wing there are two bull's-eye circles, one smaller
than the other, which form the most conspicuous feature in the marking
of the insect.
When full grown the caterpillars are a little more than an inch long
with a general color of velvety black, marked with fine yellow lines
and more or less covered with bristly spines. There is also a distinct
row of whitish spots along each side beginning a short distance back
of the head.
This is a widely distributed butterfly, occurring from Canada to the
Southern states and beyond. In most northern regions it seems to be
two-brooded, the butterflies commonly hibernating as adults; but
sometimes the winter is passed in the condition of the chrysalis.
Along its southern range there are three and perhaps four broods each
year.
=The Painted Lady or the Cosmopolite=
_Vanessa cardui_
Our story of this beautiful butterfly ought really to begin with that
of one of the most successful plants in the world. Now a plant is
successful from its own point of view when it is able to multiply
abundantly in many different sorts of situations and to spread easily
over a large area. The plant I have in mind is the thistle, which
from time immemorial has been one of the commonest neighbors of man.
It is found over the whole habitable globe, as well as in many parts
which are scarcely habitable. It has many advantages in its struggle
for life. The roots penetrate deeply into the soil; the thickened,
spiny leaves are so protected by their juices and their spines that
they are molested by very few enemies; the flower stalks are also
clothed in a similar armature; and the great heads of flowers are
surrounded with prickly involucres that generally prevent their being
eaten by browsing animals or even by phytophagous insects. The
brightly colored blossoms are abundantly provided with nectar and
pollen, and they attract great numbers of bees, moths, and
butterflies, in order to bring about cross-fertilization. But all of
these advantages are of little significance so far as wide
distribution is concerned, compared with the feathery seeds which are
produced in such abundance and so generally scattered by the slightest
breath of wind that the word thistle-down has come into general use to
express a lightly moving object. These airy seeds have been riding on
the wings of the wind all over the surface of the earth for untold
millions of years. Doubtless during severe storms they may be carried
thousands of miles, and it is easy to think that one of them might
readily go half-way round the world before it found a resting place.
Wherever such a seed alighted and found the condition of a moist soil
and slight protection, it would be likely soon to spring into growth
and to start anew the development of its ancient race.
The thistle, however, has not been entirely unmolested during its
aeons of existence. There has been developing along with it one of
the most beautiful of our butterflies which has received various
scientific names and the common name of the Painted Lady, although it
is also often called the Thistle Butterfly and the Cosmopolite, which
latter title perhaps is to be preferred. This butterfly, however, can
scarcely be considered a troublesome enemy of its host plant, for it
is seldom sufficiently abundant to injure the thistle appreciably. The
relation between the two is rather suggestive of that mutual
toleration by which two living things develop together with advantage
at least to one and without serious disadvantage to the other. The
universal distribution of the food plant has led to a like
distribution of the butterfly. Consequently the Thistle butterfly has
long been recognized as the most cosmopolitan species of its group.
(_See plate, page 176._)
Aside from the wide distribution of its food plant and possibly
correlated with it through the diversity of climatic conditions under
which the insect has developed, this butterfly is remarkable for its
powers of flight. Many instances are known where it has been taken at
sea long distances from land. This is due not only to the propensity
of the individual for taking aërial journeys, but also to the fact
that this is one of the butterflies which has the instinct to
congregate in swarms and to migrate long distances when thus
congregated. In 1879 such a flock started from Africa and migrated to
Europe.
One of the most remarkable things about this butterfly is our
ignorance of what it does with itself in winter. American
entomologists are agreed that the adult butterfly hibernates, but
where it does so seems not to be known. Here is an excellent
opportunity for some young naturalist to go scouting, hunting in board
piles, under loose bark, or with a flashlight searching the interiors
of hollow trees to find between November and April living specimens of
this butterfly. Such a discovery would be a real service to science
and should at once be made known through some scientific journal. In
Europe there seems to be a belief that the insect hibernates partially
at least in the condition of the chrysalis.
_The Life-story_
While we may not know just where the butterflies have been throughout
the winter, we do know that in southern New England they begin to be
seen in fields and along roadsides about the middle of May. Many of
the specimens then have a ragged appearance which is a pretty good
indication that they came from the chrysalis the fall before and have
been lying concealed through all the weeks since. These butterflies
lay their small greenish, barrel-shaped eggs on the leaves of the
thistle. The mother butterfly chooses the location rather carefully
and deposits only one egg upon a leaf. The butterflies continue thus
to visit flowers and to lay eggs until about the middle of June when
apparently they perish.
About a week after the egg has thus been laid, it hatches into a small
spiny caterpillar which does not take the trouble to devour its egg
shell as so many other caterpillars do. Instead it crawls around to
the lower side of the leaf and gnaws off enough of the silken surface
of the leaf to furnish material for making a webby covering, the leaf
particles being woven together by threads from the caterpillar's
mouth. In this way the little creature soon provides itself with a
snug enclosure which serves it as a temporary home. It remains in this
home much of the time when not eating, going out occasionally to feed
upon the green tissues of the adjacent parts of the leaf.
This first home of the young caterpillar, made as it is as a flat
blanket upon a flat surface, can be used only by a very small larva.
Consequently, the caterpillar soon finds these quarters too cramped
and it deserts them to make a new home with larger space. This second
nest is commonly made on the upper surface of a leaf, the edges of
which are likely to be more or less drawn together and other supports
connected from other leaves or a near-by stem. The caterpillar
continues to use this nest number two as a place for remaining when
not feeding and for protection during the process of moulting. But
even this larger nest is likely to be given up about the time the
caterpillar becomes half grown, and a third nest is begun in the upper
part of the plant. This is likely to be very commodious, its walls
being made of leaves or stems bound together by a silken web. Within
this the caterpillar completes its growth, going out and in through
one or more doors when it wishes to feed. Sometimes it even remains
within this nest during the process of changing to the chrysalis,
hanging downward from the upper part in much the same way that the
caterpillar of the Painted Beauty butterfly does. In case it leaves
the nest when fully developed it generally finds a place near-by in
which to pupate.
About ten days after the caterpillar has changed to a chrysalis it
changes again to the adult butterfly. In southern New England these
butterflies appear about the middle of July and lay eggs soon
afterward, these eggs hatching into butterflies that change to
chrysalids and change again to butterflies late in August or early in
September. This autumn brood doubtless furnishes the butterflies that
will be seen upon the wing the following May, so that it is pretty
certain that they must find some shelter in which to pass the
intervening months.
The full-grown caterpillar of the Thistle butterfly is about one and a
quarter inches long and of a general yellowish color, more or less
marked with blackish as well as with paler lines of color. There are
many transverse rows of spines along the segments, each yellowish
spine having a circle of smaller ones at the top.
Notwithstanding its fondness for thistles, these caterpillars
occasionally feed upon various other plants. One might readily expect
them to be able to live upon other composites upon which they are
found, but it seems a bit strange that they should be recorded as
being "especially fond of mallows."
=The Mourning-cloak=
_Vanessa antiopa_
One of the most scholarly students of American insects has happily
called the butterflies "the frail children of the air." It seems a
fitting term for creatures so ethereal that they are readily wafted on
the wings of the slightest breeze and so delicate in structure that
they are likely to be sadly mutilated by the lightest touch of human
hand. Such creatures one would say belong to regions of perpetual
summer and have no place in the blizzard-swept winters of our Northern
states.
Yet if one goes into the snow-clad woods during one of the midwinter
thaws one is likely to see in every open glade several dark-colored
butterflies flitting from tree to tree, or resting with expanded
wings in the sunniest spots. These butterflies obviously have endured
the coldest weather and if they are to survive until another season
must continue to endure still more. This species is commonly called
the Mourning-cloak butterfly--not a particularly happy name for so
beautiful an insect. In England it has the more suggestive title of
Camberwell Beauty, and country boys are said to call it the Yellow
Edge butterfly. Its general life-story has already been told on pages
112-115.
The caterpillars of the Mourning-cloak butterflies are restricted to
comparatively few food plants. In regions where they are not
especially abundant, they are likely to be found upon willow, poplar,
or elm. In general, as many observations indicate, they are as likely
to be found upon any one of these food plants as upon either of the
other two; but in certain localities where they become especially
abundant it seems that they are more likely to occur upon the elm. On
this account they have been called the Spiny Elm caterpillars. There
is considerable evidence to show that they prefer the American elm to
other species of the genus, although in the case of willow and poplar
there seems to be little if any preference as to the species.
Miss Caroline G. Soule has seen the butterflies depositing their eggs
upon the white and canoe birch, and it has been recorded as feeding in
Labrador and Europe upon a species of birch. There is one record of
the caterpillars having been found feeding upon the hackberry, and
also of their having fed greedily upon the leaves of rose bushes, and
still another of their having almost defoliated a pear tree. Linden
and nettle are also included in the European lists of the food plants
of this species. (_See plates, pages 145, 176._)
It is evident, however, that all of these, except the three first
named--willow, poplar, and elm--are to be regarded as exceptional
cases, and that the normal food of the species is the foliage of a
plant belonging to one of these three genera.
It has generally been supposed that this species is double-brooded in
central and southern New England, the butterflies of the first brood
appearing early in July. These are said to deposit eggs which hatch
into caterpillars that mature into butterflies early in September.
These butterflies live through the winter, laying eggs the following
spring.
It is very probable that as far north as southern New Hampshire the
species is commonly single-brooded. During one season when the
caterpillars were unusually abundant, a very careful watch was kept
for the second brood in New Hampshire and Vermont by several competent
observers. Only one colony of caterpillars was found and this was at
Durham in the southern part of New Hampshire near the seacoast.
Consequently, it seems safe to conclude that in northern and central
New England, at least, a single brood is the rule rather than the
exception. This involves the conclusion that the butterflies seen upon
the wing early in autumn are the same ones that developed in July, and
that these same butterflies remain alive through the winter and until,
in the following May, they lay their eggs. Thus there is a period of
ten months of existence in the butterfly state, an extraordinary
length of time for a butterfly to live.
To a large extent the butterflies disappear in August, and the
question arises as to what becomes of them. Our observations lead to
the conclusion that they go into summer quarters similar to those
which they seek out for winter shelter. Apparently they fly about for
a few days after coming from the chrysalis and then retire to cool
woods, where under the side of a log or beneath the loose bark of a
dead tree they settle down and to all appearances go to sleep. The
instinct to remain quiet is very strong in these butterflies. In
taking the accompanying photographs, I found that even shortly after
coming from the chrysalis the butterflies when disturbed would fold
their wings with the antennae between them, and drawing the legs
against the body would lie quietly on their sides for a long time.
These same butterflies would also hang downward from a limb by the
hour in the hibernating position as shown in plate opposite page 32.
In the cooler weather of early autumn, the butterflies come from their
retreats and fly about in the sunshine. They are especially likely to
be seen along the borders of woods or in open glades. At this time
they love the sunshine, and will settle in a sunny place to bask in it.
_Going into Winter Quarters_
When the warm days no longer tempt them abroad, the Mourning-cloaks
seek shelter in many sorts of situations--under loose bark, in hollow
trees, under culverts and bridges, in woodpiles, in crevices of rocks,
or alongside logs lying on the ground. In such retreats they remain
until the sunshine of spring again calls them forth.
Prof. G. H. Parker's observations indicate that these butterflies are
very sensitive to changes of temperature, and he has seen the
interesting action of the butterflies crawling into their hiding
places, finding that this takes place each day after they had been
sunning themselves. Thus he writes:
"These butterflies remain during cool spring nights in places similar
to those in which they hibernate in winter, _viz._, in openings in
stone walls, in old out-houses, in openings under the bark of trees,
etc. They retire to these places with considerable regularity, so that
in the open woods, where dozens of individuals may have been seen
flitting about, all may have disappeared a quarter of an hour later. I
have watched their retreat with some care. On a clear afternoon in
early April I took my stand in a woodland where many Mourning-cloak
butterflies were on the wing. They continued actively flying about
till approximately four o'clock, when I began to notice a diminution
in their numbers. By a quarter past four not a butterfly was to be
seen. During the fifteen minutes from four o'clock on I followed two
to their hiding places. One alighted on the front of a fallen tree and
without expanding its wings crept immediately into a large crack in
the bark. The second settled on a stone fence and crept into a hole
between some loose stones. The period during which this occurred was
marked not so much by a diminution of light as by a rapid fall of
temperature."
That the habit of lethargy in cold and of resting upon the bark of
trees is practically universal with this species is shown by a
statement quoted by H. G. Adams in his book, "Beautiful Butterflies,"
published in England in 1871. The writer quoted says: "In a wood on
the summit of the Drachenfels, when the wind was rather keen, I found
numbers resting on the backs of fallen trees in a state of stupor.
They made no attempts to escape and when thrown into the air their
wings barely opened or flapping feebly eased their fall or enabled
them to seek repose on the stem of a rotten trunk."
_Its Rarity in England_
In many books this species is spoken of by its English name Camberwell
Beauty. It is so called because it was first observed in the
neighborhood of Camberwell in the county of Surrey, England. It seems
that in that country it is a very rare species. This is a bit curious
considering the fact that in America it is so extremely abundant. In
his attractive little book quoted above, Mr. Adams begins the
discussion of this species with this statement: "This is the crowning
glory of the British butterfly collector's cabinet, and a happy man is
he who gets a perfect specimen of an insect which is at once so rare
and so beautiful." And later in the same discussion is this further
statement concerning the scarcity of the species: "In neither the
larva nor the pupa state has the insect been found, we believe, in
this country where its appearance occurs, except just here and there a
single specimen or two, at long and uncertain intervals. About eighty
years ago it was seen in many parts of the kingdom and again in 1819,
but not since then although almost every year one or more specimens
are taken or seen."
A curious fact in regard to the Mourning-cloak, as found in England,
is that the border around the wings seems to be much more generally
white than it is with us. J. O. Westwood in his book on British
butterflies describes the margin as of a white or whitish color and
other writers speak of the same fact. Kirby in his "Butterflies and
Moths" makes this comparative statement: "The border is whitest in
British specimens, and perhaps yellowest in American ones." He speaks
of it also as one of the rarest British species. It is sometimes
called by the common name the White Border and also occasionally the
Grand Surprise, appellations which bear out what has been said above
both in regard to the color of the border and the rarity of the
insect.
[Illustration: THREE MORE ANGLE-WINGS
Upper surfaces at left; under surfaces at right, slightly reduced
The Buckeye (_see page 188_)
The Painted Beauty (_see page 163_)
The Cosmopolitan (_see page 166_)]
[Illustration: _From a drawing by W. I. Beecroft_
_See pages 112, 171_
THE MOURNING-CLOAK
Caterpillar, chrysalis, and butterfly]
The Mourning-cloaks subsist upon a considerable variety of liquid food
which they suck through their long tongues. In spring, when they first
come from their winter quarters, they visit the stumps of recently cut
trees and suck the exuding sap, a habit which they continue whenever
opportunity offers. Mr. W. F. Fiske has noticed that they commonly sip
the sap of maple twigs where the squirrels have gnawed the bark. A
little later they visit the willow catkins to suck the nectar secreted
by these blossoms, and still later they hover about the delicate
blossoms of the mayflower, or trailing arbutus, for a similar purpose.
Probably many other flowers are thus rifled of their sweets, although
this butterfly seems to be a less regular visitor to flowers than are
many of its allies. A little later, when the aphids, or plant-lice,
have become sufficiently abundant so that the so-called "honey dew" is
to be found upon the infested shrubs, these Mourning-cloaks sometimes
sip the liquid sweet from the surface of the leaves. In April and May
they occasionally visit the flowers of moosewood, and later in the
season have been observed upon the blossoms of the common milkweed.
From the time the early apples ripen these butterflies may often be
seen beneath the orchard trees, sipping the liquids of the fallen and
decaying fruit.
_The Parasites of the Eggs_
One fine spring morning I came upon a Mourning-cloak depositing a
cluster of eggs upon a willow twig. She was so busily engaged that I
was able to draw near and watch the operation for some time before she
flew away. As soon as she was gone I was much interested to see a tiny
parasitic fly running eagerly over the newly laid eggs, and this fly
also was so busily interested in her work that I was able to cut the
twig off and sit down to observe at leisure through a lens the actions
of the insect. I dictated to a companion my notes of these
observations and so was able to get rather a complete record of the
process of oviposition.
The tiny fly would stop over one of the butterfly eggs, holding its
body vertical with the hind legs far back and the other legs so
straightened out as to hold the front of the body high up. Then it
would insert its tiny ovipositor through the egg shell and proceed to
deposit an egg of its own inside of the larger egg of the butterfly.
At least it seemed a safe assumption that this was what happened
although of course it was impossible to see the smaller egg at the
time. While thus engaged the antennae of the tiny fly were bent
directly downward to the egg beneath. In about a minute the fly
withdrew its ovipositor and after running around for a few seconds
again settled upon another egg and repeated the operation. Then it
tried again on a third egg, after which I got out my watch and began
timing the process. These are the results in the case of the next
dozen eggs that were laid. It required:
94 sec. to lay egg No. 4. Then fly moved around 26 sec.
120 " " " " " 5. " " " " 27 "
83 " " " " " 6. " " " " 20 "
92 " " " " " 7. " " " " 22 "
75 " " " " " 8. " " " " 40 "
90 " " " " " 9. " " " " 42 "
102 " " " " " 10. " " " " 15 "
120 " " " " " 11. " " " " 21 "
120 " " " " " 12. " " " " 18 "
60 " " " " " 13. " " " " 25 "
120 " " " " " 14. " " " " 25 "
60 " " " " " 15. " " " " 50 "
It thus required an average of about two minutes per egg for the
laying of these fifteen eggs. I then caught the little fly and sent
her to Dr. L. O. Howard, our greatest authority on this group of
insects, to learn the name of the parasite. He identified it as
_Telenomus graptae_, a well-known parasite of the eggs of the
Mourning-cloak and related butterflies.
The most interesting thing about this observation was the fact that
the little fly had apparently begun its operation before the mother
butterfly had finished laying her cluster of eggs. There were
thousands of willow twigs in the immediate vicinity. How did this tiny
creature arrive at this particular place at the particular moment when
from its own point of view it was most needed? Had it been riding
around upon the body of the butterfly waiting for the time when she
should lay the eggs? Or was it attracted to them from somewhere in the
immediate vicinity? That this early arrival probably takes place
generally is indicated by the fact that a similar observation had been
made in the White Mountains by Prof. C. W. Woodworth.
The history of the egg parasite after the laying of the egg seems to
be comparatively simple. It soon hatches into a tiny larva that
develops within the shell at the expense of the contents. It finally
changes to a pupa which in turn changes to the little fly that gnaws a
hole through the egg shell and emerges to the outer world.
_The Parasites of the Caterpillars_
After hatching from the egg, the Mourning-cloak caterpillars are also
subject to the attacks of various parasites. One of these is quite
minute, not a great deal larger than the egg parasite. It is a tiny
four-winged fly which deposits many eggs in a single caterpillar. The
eggs hatch into tiny maggots that grow at the expense of the
caterpillar, finally killing it and changing to four-winged flies
again. As many as 145 of these parasites have been known to emerge
from a single dead caterpillar. These little flies are called Chalcids
by entomologists.
There is still another group of four-winged flies, some of which
attack the Antiopa caterpillars. These are much larger than the
Chalcid flies and are called Ichneumon flies. In the case of these,
only one or two parasites develop in each caterpillar or chrysalis.
In addition to these various four-winged flies, there are certain
two-winged flies, called Tachinid flies, that develop at the expense
of the caterpillars. In New Hampshire, during recent years, these
appear to have been the most abundant parasites of these insects. An
egg is laid on the skin of the caterpillar by a two-winged fly,
similar in general appearance to the figure below. The contents of
this egg shortly develop into a tiny grub that burrows through the egg
shell and the skin of the caterpillar into the inside of the body.
Here it remains, absorbing the body substance of its host and
gradually increasing in size. In a few weeks it becomes fully
developed in this grub state. By this time the caterpillar has become
sluggish from the effects of the parasite. If the branch upon which it
feeds is disturbed, the other caterpillars are likely to crawl away,
but the enfeebled victim remains in its place.
[Illustration: Tachinid Parasite. (Slightly magnified.)]
Shortly after becoming full grown, the Tachinid grub breaks through
the skin of the dying caterpillar and, falling to the ground, changes
to a peculiar pupa; the outer skin of the grub turns brown and becomes
hard, forming a protective covering for the body inside. A week or two
later the insect undergoes another change and emerges as a two-winged
Tachinid fly, like the one that laid the egg some weeks before.
_Other Enemies_
Besides those insects that develop on the inside of the bodies of
these Antiopa caterpillars there are other insect enemies which attack
them from the outside and devour them bodily. The most notable of
these, perhaps, is a large beetle commonly called the Caterpillar
Hunter; it is known to entomologists as _Calosoma scrutator_. This is
a very active insect, with large strong jaws, that runs rapidly about
in search of victims. In some cases it has been observed while
destroying many of the Antiopa larvae.
In the Southern states a common reddish wasp--a species of
Polistes--has also been observed attacking these caterpillars, and
there are probably various other insects that destroy them, although
definite observations showing this have not been recorded.
The Antiopa caterpillars are such spiny creatures that comparatively
few birds attack them. They are devoured, however, by the two species
of cuckoos--the yellow-billed and black-billed--and it is probable
that they are sometimes killed by Baltimore orioles and various other
birds. They are also greedily devoured by toads, but of course they do
not often come within the reach of these useful animals.
Even the adult butterflies of this species have to be on the lookout
for enemies. During the long months of their life many of them
probably succumb to the attacks of birds or other creatures. I have
seen but one such tragedy. While riding along a country highway with a
bird-loving friend one spring day we saw a male Maryland yellow-throat
flit by with a Mourning-cloak in his mouth. The bird lit on a fence,
from which I startled him so that he dropped the butterfly, a worn and
faded, half-dead specimen. The places where the bird held the insect
were indicated by missing pieces of the wings.
=The American Tortoise-shell=
_Aglais milberti_
This beautiful butterfly is one of the most distinctive of all our
species. It is of moderate size, its wings rarely expanding more than
two inches, and it has sufficiently irregular outlines to indicate its
relationship with the Angle-wings. The most striking feature of the
upper surface is the broad band of orange-brown extending clear across
both wings a little inside the border. The remaining surface is a
darker brown marked with two orange-brown spots near the front margin
of each front wing and having scattered iridescent scales which show
plainly under a lens. The suggestion of the coloring of a
tortoise-shell is easily seen in these rich brown tones. The under
surface is a wonderful illustration of protective coloring. With wings
closed and resting against the bark of trees or lying beneath the
trees among fallen leaves, it would require a keen eye to detect the
insect. (_See plates, pages 160-161._)
The American Tortoise-shell is distinctly a northern species. North of
latitude forty-three degrees it seems to occur practically from ocean
to ocean, extending far up toward the arctic region. It is commonly
found in British America as far north as Fort Simpson in latitude
sixty-one degrees. There are specimens in the British Museum collected
by the explorer Ross in arctic America, and there are many in our own
National Museum collected in the Hudson Bay region by various American
explorers. In New England the species is abundant at times in New
Hampshire, Vermont, and Maine. In the vicinity of New York City and
Buffalo, New York, it is rather rare. And south of this latitude it is
found chiefly at the higher elevations in mountainous districts. As a
rule it is likely to vary in numbers from year to year, sometimes
being extremely abundant while more commonly it is rather rare. These
are the same sorts of fluctuations that we find in the case of the
Mourning-cloak, the American tent caterpillar, and various other
insects whose larvae live in colonies. The variation is probably due
to the fact that when the caterpillars become unusually abundant they
become correspondingly conspicuous and so provide a shining mark that
is soon discovered by their insect enemies or by various fungous
diseases.
_The Story of Its Life_
In its manner of laying eggs this butterfly differs from most others.
The great majority of our familiar species lay their eggs one in a
place or possibly two or three near together. Some species deposit
several in a group, while some, like the Mourning-cloak, may lay two
or three dozen in a cluster. Very few, however, deposit hundreds in a
bunch. Two of these are the Baltimore and this American
Tortoise-shell. In the case of the latter the eggs are loosely laid,
hundreds together, upon the leaves of the common stinging nettle.
Probably each female can deposit six or eight hundred eggs. In less
than a week the eggs hatch into minute blackish caterpillars that feed
upon the tender tissues of the leaf upon which they were born and then
migrate together toward the top of the plant. In their habits they are
quite similar to the caterpillars of the Mourning-cloak. As each walks
it spins from its mouth a silken thread and the combined effect of
hundreds of these threads is to make a noticeable silken web over the
leaves. The caterpillars remain in colonies, feeding together from day
to day and gradually denuding the upper branches of the nettle plant,
leaving an unsightly silken web as a memento of their presence. This
webbing is very suggestive of the similar result left behind by a
colony of Mourning-cloak caterpillars upon the twigs of elm or poplar.
When about half grown these caterpillars are likely to scatter more or
less in accidental groups which may make small shelter tents from the
larger leaves. In each little nest there may be four or five or more
of the dark-colored caterpillars. From these shelter tents they sally
forth to feed upon the adjacent leaves and a little later become full
grown as caterpillars. Each now wanders away and finding such shelter
as it is able to, spins a button of silk and becomes a chrysalis. It
remains in this condition but a short time before it emerges again as
the beautiful butterfly.
This species is commonly reputed to have three broods a year,
hibernating both as a butterfly and as a chrysalis. It has been
suggested, however, by Mr. W. F. Fiske, one of our most painstaking
entomologists who has studied the butterflies of New Hampshire for
many years, that it is more probably double-brooded with a period of
aestivation during the later weeks of summer. This seems a very
probable condition and it is to be hoped that some observer will make
such a careful study of this species as to settle the point
definitely.
In the case of many butterflies the distribution of the species
coincides with the distribution of the food plant. This American
Tortoise-shell, however, is perhaps the exception that may prove the
rule, for its southward limit is far north of the southern range of
the stinging nettle. Evidently, it is a species which has developed in
adjustment to the cool climate of northern regions or high altitude,
and it does not easily adapt itself to a warmer territory.
=The White-J Butterfly or Compton Tortoise=
_Eugonia J-album_
During bright days in March and April one is likely to find two kinds
of butterflies on the wing in open glades of the woods. One is the
familiar Mourning-cloak and the other is the Compton Tortoise--the
latter generally much less abundant than the former. Both make the
most of the brief periods of sunshine and quickly disappear when the
sky is overcast.
The Compton Tortoise butterflies which are thus abroad in early spring
have been in hibernation since October. They are helping to carry the
species over from one season to another, and as the days become longer
and warmer they appear on the wing more and more, seeking such liquid
food as the field and forest yields during the days of early spring.
The sap exuding from holes in bark made by woodpeckers, or from the
tappings of the maple trees by man, the nectar of willow catkins, the
moisture of roadside pools--these help to yield a precarious
sustenance to these butterflies after their long winter fast. They
remain upon the wing week after week, while spring slowly progresses
in the northern regions they inhabit. When at last the leaves push out
on their food trees--willow, birch, and elm--the females lay their
eggs and then, having lived to what for a butterfly is a ripe old age,
they die, after nearly ten months of adult existence.
Apparently the eggs are laid in clusters on the twigs, although this
seems to be one of the many facts about butterflies awaiting
observation by some careful student. The caterpillars feed together in
small colonies but make no nest. They become full grown in about a
month. They are then nearly two inches long with spinous, greenish
bodies, striped with lighter lines. Some change to chrysalids about
the middle of June and ten days later change again to butterflies, the
first of which appear early in July while others continue to emerge
for nearly a month.
These butterflies may be seen rather frequently from midsummer on,
visiting various flowers and sipping the juices from decaying fruits
beneath the trees. At times they seem to disappear in August to
reappear in October, a fact which has led some observers to suggest
that there is a second brood. The caterpillars of this brood, however,
have never been observed and a much more probable explanation has been
made by Mr. W. F. Fiske who studied the butterflies of New Hampshire
carefully for many years. He found that in the hot summer weather this
butterfly goes into a seclusion similar to that of its winter
rest--that is, it aestivates in summer and hibernates in winter. "The
possibility that the October J-album did not represent a second
brood," writes Mr. Fiske, "was rendered almost a certainty by repeated
observations which failed to disclose a single specimen approximating
in freshness to average August individuals, and the question of their
whereabouts during the interim was unexpectedly answered one warm
August day by my finding several snugly packed away under the shingles
on an old roof. The theory of the aestivation of the butterflies of
this group will explain a good many points hitherto obscure in the
life histories of the other species."
In October these butterflies seek their winter quarters, finding them
in woods and groves. Apparently they commonly rest upon the bark of
the trunk as well as crawl into such crevices beneath loose bark as
they can find. Here they remain through fall, winter, and spring,
except when called into brief periods of activity by the unwonted
warmth of the winter sunshine. Then in spring they come forth again to
lay the eggs for the caterpillars of the new generation.
The fresh butterflies are creatures of exquisitely modulated coloring.
The name Compton Tortoise has reference to the rich brown tones of the
upper wing surface, suggestive of those of fine tortoise-shell. In
fresh specimens much of the surface, especially in the middle and
along the front border, is overlaid with iridescent purple scales.
Near the front outer angle of each of the four wings there is a
distinct white spot, divided near the middle by a darker line of the
vein running through it. The under surface is one of the best examples
of mimicry of gray bark to be found in any butterfly. The tones vary
considerably in different individuals, but in all the protection must
be well nigh perfect when the insect is at rest with closed wings upon
the bark of a tree. The striking angularity of the wing's border
doubtless helps to conceal it, and the habit of dropping motionless to
the ground when disturbed must also have protective value. Near the
middle of each hind wing there is a small white J which led to the
specific name _J-album_.
This butterfly is essentially a member of the Canadian fauna. It
ranges from far north in Labrador, British America, and Alaska, south
as far as Pennsylvania, but toward its southern limit it occurs only
on the higher elevations of mountains like the Alleghanies.
=The Buckeye=
_Junonia coenia_
Some genera of butterflies seem to belong almost exclusively to the
north temperate regions, seldom occurring even in our Southern states.
Others belong equally exclusively to tropical regions, seldom
straying into the north. The Buckeye is an illustration of the latter
group. The genus Junonia to which it belongs is essentially tropical,
as it contains several species which are found throughout the tropics
in both the Old and the New Worlds. In fact, this is apparently the
only species which occurs north of the tropics. It has an
extraordinary range, being found from Cuba to Massachusetts and from
the Atlantic to the Pacific coasts. Toward the northern limits of its
range it is very rare and one of the greatest prizes which the
collector can obtain. In our Southern states it is an abundant and
generally distributed butterfly and, as it hibernates as an adult and
one group follows another throughout the season rather rapidly, it is
likely to be taken at almost any time. (_See plate, page 176._)
The mother butterflies select as food plants for the larvae various
members of either the plantain or figwort families. They lay eggs, one
in a place, upon the leaves of plantain, figwort, gerardia, and
related plants generally near the tip of the leaves. Less than a week
later these hatch into spiny caterpillars which feed upon the green
substance of the leaves during the next few weeks. For the most part
they eat between the veins leaving a ragged effect which may help in
finding them. When full grown they change to chrysalids which hang
straight downward and bear a general resemblance to those of the
Thistle butterfly. Curiously enough, those chrysalids which are
attacked by parasites take on a characteristic golden hue; although
the normal healthy chrysalids are dark brown with a few touches of a
decidedly lighter brown.
In its tropical home, where there is no winter period to interrupt its
growth, this butterfly doubtless continues to develop generation
after generation without any break in the sequence. As the species
goes north, however, there is necessarily such an interruption--in
which case the winter seems commonly to be passed by the adult
butterfly. In our Southern states there are commonly three or four
broods each year, while in the northern parts of its range there is
but one brood a year. In the South there is such an overlapping that
all stages of the insect may be found at one time.
_Synopsis of the Angle-wings_
_I. The Polygonias_
The most angular of the Angle-wings are grouped in the genus
Polygonia. They are characterized by having the outer margin of the
front wings projecting in two places in a way to give an angular
effect, and by having the hind or inner margin distinctly excised
toward the outer end, so that this margin is curved rather than
straight.
_Violet-tip_ (_Polygonia interrogationis_ or _Grapta
interrogationis_). Expanse 2 1/2 inches. Under surface of each hind
wing marked by a silvery semicolon, made up of a dot and a crescent.
_Hop Merchant_ (_Polygonia comma_ or _Grapta comma_). Expanse 2
inches. A white comma with expanded tips on lower surface of each hind
wing. Lower surface of all the wings mottled with brown.
_Green Comma_ (_Polygonia faunus_ or _Grapta faunus_). Expanse 2
inches. A white comma with expanded tips on lower surface of each hind
wing. The lower surface of all the wings more or less mottled with
green toward the margins.
_Gray Comma_ (_Polygonia progne_ or _Grapta progne_). Expanse 2
inches. A white comma with tips narrowed rather than expanded on lower
surface of each hind wing.
_II. The Vanessids_
Our beautiful species of the genus Vanessa may be known by the long
scales that make up the fringe on the wing margins, in alternate
groups of black and white. There are also several white spots on the
upper surface of the outer angle of each front wing.
_Red Admiral_ (_Vanessa atalanta_, _Pyrameis atalanta_ or _Cynthia
atalanta_). Expanse 2 inches. Upper surface of front wings blackish,
marked with white spots on outer angle and a broad orange stripe
across the middle.
_Painted Beauty_ (_Vanessa huntera_, _Pyrameis huntera_ or _Cynthia
huntera_). Expanse 2 1/2 inches. Upper surface orange-brown with
black, white, and blue markings. Lower surface of each hind wing with
two large eye-spots, each extending across two veins.
_Painted Lady_ or _Cosmopolite_ (_Vanessa cardui_, _Pyrameis cardui_
or _Cynthia cardui_). Expanse 2 1/2 inches. Easily distinguished from
the Painted Beauty by the four or more small eye-spots on the lower
surface of each hind wing, each eye-spot being included between two
veins.
_III. Other Angle-wings_
The other common Angle-wings are readily distinguished by the
following characters:
_Mourning-cloak_ (_Euvanessa antiopa_ or _Vanessa antiopa_). Expanse
3 1/2 inches. Easily known by the nearly black wings with creamy white
borders.
_American Tortoise-shell_ (_Aglais milberti_ or _Vanessa milberti_).
Expanse 1 1/2 inches. One of the smallest of the Angle-wings. Easily
known by its small size and the broad orange band extending across the
upper surface of all the wings just beyond the middle. Under surface
dark mottled gray without distinct white markings.
_Compton Tortoise_ (_Eugonia j-album_, _Vanessa j-album_ or _Grapta
j-album_). Expanse 3 inches. Best known by the straight line of the
inner margin of the front wings and the white j on the under side of
each hind wing.
_The Buckeye_ (_Junonia coenia_ or _Vanessa coenia_). Expanse 1 3/4
inches. Distinguished by the large eye-spots on the upper surface of
the wings, one on each front and two on each hind wing. Eyes not
hairy.
THE TRIBE OF THE SOVEREIGNS
No other small group of American butterflies has attracted so much
attention as the species of the genus Basilarchia, which have been
happily called the tribe of Sovereigns. These are rather large
butterflies with rounded wings which are found in one species or
another over practically the whole of North America. Some of them are
of exceeding beauty and all of them present life-histories of
extraordinary interest. At least two of the species are the most
notable examples of the mimicry of other butterflies that are shown in
our fauna. They also present some extremely interesting problems for
the study of natural hybrids and they illustrate in their development
some of the most wonderful cases of adaptation to environment that
have ever been found.
[Illustration: _From a drawing by W. I. Beecroft_
_See pages 268-282_
SOME COMMON SKIPPERS
The Long Dash, male, at top; the Vitellius Skipper, female,
next below; the Canadian Skipper resting on iris flower in the
middle; the Least Skipper, next below; Leonard's Skipper at
rest on leaf, next; and the Sachem Skipper, male, at bottom]
[Illustration: _From a drawing by W. I. Beecroft_
_See pages 195-202_
THE STAGES OF THE VICEROY
The butterfly freshly emerged; caterpillar hung up for
pupation; the chrysalis; the caterpillar feeding]
These butterflies may be considered from so many interesting points of
view that it is a bit difficult to know which phases to emphasize. In
general, there is a striking similarity in their structure and habits
in the earlier stages. The eggs are very nearly alike; the
caterpillars resemble one another so closely that even expert
entomologists sometimes have to decide what species a collected
caterpillar belongs to by seeing what plant it is feeding upon, and
the chrysalids are also very similar.
Some of the more interesting phases in the development of these
insects are discussed in connection with the life-stories of the
different species. A phase which is characteristic to all of them may
well be emphasized here. From the time the caterpillars hatch until
they change to chrysalids they illustrate to a marked degree an
adaptation through structure and habit which must very largely protect
them from attack by birds and other enemies. Their structure and
markings are almost grotesque. The body is covered with strange
club-like appendages and it is colored with a curious mottling of
tones of green, drab, brown, and white which is very difficult to
describe but which suggests, as the caterpillar rests upon rough bark,
simply a bit of bird dung or some natural excrescence. The
caterpillars have the habit of feeding at night and remaining upon
their perches by day, often assuming positions which are very unusual
among insect larvae. Such positions, in which they remain motionless
for hours at a time, are undoubtedly of protective value and help to
conceal the insect. After the caterpillars are half grown they rest
not upon the leaves upon which they feed, but rather upon the bark of
twigs or branches where their peculiar structure is likely to make
them inconspicuous.
The chrysalids of the Sovereigns are also curiously mottled in color
tones that will probably lead to their being overlooked.
Three distinct species of Sovereigns are found in eastern North
America, namely:
The Viceroy, _Basilarchia archippus_.
The Banded Purple, _Basilarchia arthemis_.
The Red-spotted Purple, _Basilarchia astyanax_.
The first species, the Viceroy, has a much wider distribution than
either of the others. It apparently is found in nearly all localities
in which either of these occur, and so includes within its range
almost the whole of the United States and much of Canada.
The second of these, the Banded Purple, is a northern form. It is
found commonly at least as far north as the Mackenzie River region in
British America and southward to central Massachusetts. It also occurs
as far west as Nebraska so that it has a very wide distribution in
northern regions. It is especially abundant in Canada and the White
Mountains.
The third, the Red-spotted Purple, is the characteristic form south of
latitude 42 degrees. Its range overlaps that of the Banded Purple for
about one degree but it is seldom found north of latitude 42 degrees.
It seems to range about as far west as the Banded Purple.
There are several other butterflies belonging to this genus which are
rarely found and which occur only in certain limited regions. There
has been much discussion in regard to these. Some entomologists have
thought them simply varieties or dimorphic forms while others have
considered them hybrids. An analysis of the conditions shows that
these doubtful butterflies occur only in regions where the different
species overlap. Thus in the boundary connecting the Banded Purple
and the Red-spotted Purple there are forms which resemble these two
species in such a way as to suggest that these are the parents of the
hybrid. In localities where the Viceroy and the Banded Purple occur
there are other forms which seem to connect these two species, and in
the locality where the Viceroy and the Red-spotted Purple occur there
are still other forms which seem to suggest these as the parents. So
the evidence seems pretty conclusive that where these butterflies
overlap there are likely to be occasional crosses between the species
which result in these natural hybrids.
In the far Western states there are certain other species of
Basilarchia which take the place of the eastern form. One of the most
abundant of these on the Pacific Coast is sometimes called Lorquin's
Admiral (_B. lorquini_). In Florida there is another species, _B.
floridensis_, which is found in the Southern states. It is the only
one whose coloring resembles that of the Viceroy.
=The Viceroy=
_Basilarchia archippus_
The common name of this butterfly was probably given it in allusion to
its resemblance to the Monarch butterfly. For the Monarch and the
Viceroy have been closely associated in the minds of many observers
ever since people began to study butterflies in America. These two
insects have become famous as the most notable examples that we have
of the mimicking of one butterfly by another. According to the theory
which has been held by many naturalists, the Monarch is distasteful to
birds and other animals and it advertises the fact by its bright
combination of brown and black. The Monarch is thus an example of what
has often been called warning coloration. On the other hand, the
Viceroy is commonly supposed to have no objectionable taste when eaten
by birds, but it so closely resembles the Monarch in its color pattern
and its habits of flight that it has been assumed that birds would not
touch it because of its resemblance to the distasteful butterfly.
There has, however, recently been a reaction among naturalists in
regard to the validity of many supposed examples of warning coloration
and the whole subject is still open to careful investigation. (_See
cover; and plate, page 145._)
Whether the Viceroy deserves its celebrity as an insect mimic or not,
it is well worthy of study for other reasons. It is a common and
attractive butterfly and it has most interesting habits in the larval
state. It is found over a large part of North America and flies freely
from spring until autumn over meadows, fields, and open glades.
_The Yearly Cycle of Life_
To trace the yearly cycle of this butterfly's life, let us begin with
one of the mother insects flitting along a stream in early summer. She
stops now and then to lay an egg on the tip of a leaf on a willow or
poplar. She then continues on her way occasionally sipping nectar from
any early flowers she may chance to find, and continuing her leisurely
life perhaps for several weeks.
The egg thus laid upon the poplar leaf remains in position for a week
or more, unless it should be devoured by some wandering ant or
discovered by some tiny parasite. If it escapes these dangers, it
hatches into a minute caterpillar that escapes from the egg shell
through a hole in its side. After it has come out it turns around and
eats the remainder of the shell. It then begins feeding upon the
tender tissue of the leaf it is resting upon, nibbling at the sides
until its appetite is satisfied. Then it retires to the midrib on the
lower surface where it remains quietly through the day and thereafter
feeds chiefly at night. After about a week it becomes too large for
the skin with which it was born, so it moults and immediately devours
its cast skin. It continues these operations of feeding and moulting
at occasional intervals for several weeks, finally becoming a rather
large and curious looking caterpillar, mottled in greenish olive and
light gray, with two large horn-like projections from the front of the
body.
It finally becomes full grown in this larval state. Then it spins a
web of silk upon the bark of the twig and entangles the hooked claws
of its hind legs in the silken web. It thus hangs downward until the
larval skin is shuffled off and the curious pupa with the conspicuous
hump upon the middle of its back remains in its place. This chrysalis
is of a mottled coloring, very similar to that of the caterpillar. A
week or so later the chrysalis skin breaks open, and the butterfly
comes out, catching hold of the twig with its legs and hanging quietly
in position while its wings expand.
The butterflies of this brood are likely to appear late in summer. It
is the second brood of adult butterflies for the season. These insects
have the same leisurely habits as those that were on the wing earlier
in the season. In a similar way the mother butterflies lay their eggs
on the leaves of willows and poplars, and these eggs soon hatch into
young caterpillars that look like those that hatched in early summer.
The caterpillars, however, of this autumnal brood have a most
interesting habit which was entirely lacking in those of early summer.
Soon after hatching they begin to make for themselves little houses in
which to pass the winter. This is very cleverly done by utilizing part
of the leaf upon which they are feeding. Each side of the leaf toward
its tip is eaten off with the midrib remaining untouched; then the
lower half of the leaf which has not been eaten is rolled into a tube
and securely sewed together with silken threads. The stem of the leaf
is also covered with a similar silken web and securely fastened to the
twig in such a way that it is impossible for the leaf to fall off when
the other leaves do. The little caterpillar thus cleverly provides
itself with a safe winter home into which it retreats on the approach
of cold weather to remain until spring. They enter these little cases
head first, and apparently seldom emerge again until the warm spring
sun brings them forth to feed upon the developing willow catkins or
the unfolding leaves.
The caterpillars that thus pass the winter in these pitcher-like cases
are perhaps a third grown. They develop rapidly in spring and are
likely to use the cases for resting purposes when they are not
feeding. After a few weeks they become full-grown caterpillars and
change to chrysalids, to change again a little later into the
butterflies that appear in early summer. There are thus two broods of
each stage of the insect during the year.
_Curious Caterpillar Habits_
This brief summary of the yearly history of the Viceroy is by no means
adequate as a story of the many interesting things to be told about
this insect, which has been carefully studied by several eminent
naturalists. One of these is the strange habit the very young
caterpillars have of fastening a few bits of leaf together by means of
silken threads and then tying the bunch to the denuded rib of the
leaf. To explain this, allow me to quote from an admirable essay of
the late Samuel H. Scudder, whose studies of butterflies have added so
much to our knowledge of these beautiful creatures:
"Soon after birth," wrote Mr. Scudder, "when it has eaten but a very
few swaths down the leaf, the little fellow constructs a small and
loose packet from minute bits of leaf and other rejectamenta, loosely
fastened to one another and to the midrib, close to but scarcely
touching the eaten edge of the leaf; and as fast as the leaf is eaten,
it removes this packet (continually added to until it becomes almost
as big as a small pea) farther and farther down the midrib away from
its perch, always keeping it near the eaten edge. It should be noted
that it is so loosely attached (the bits of leaf at all possible
angles) that it is moved by the least breath. Meanwhile, the
caterpillar has been growing larger and more conspicuous, and thus in
greater peril from its enemies. There are two possible services that
this odd packet may render. A spider wandering over a leaf and
observing its motion may seize it, and thinking it has a prize, hurry
away with it and leave its architect unharmed. This seems to me rather
a strained suggestion, for a wandering spider would probably proceed
to investigate it on the spot. Another explanation seems more
probable. It should be remembered that the leaves preferred by these
creatures as food are mostly such as are easily shaken by the wind,
and as the caterpillar moves with the leaf and with all the
surrounding leaves (in a continual fluttering in the case of the
trembling aspen, and to a less degree in the other food plants), this
of itself is a protection to it, as it would more readily escape
observation as an object distinct from the leaves, all being in motion
together; but on the more stable leaves, like the willow, the motion
in a feeble wind would not be sufficient to be serviceable, and here,
at least, the packet comes into play. An object in motion among others
at rest is a noticeable thing; a fact well recognized among animals,
as a host of them show when they fear being seen. This packet attached
by loose silken threads moves, as stated, with a breath of wind, and
so would distract attention from its architect near by, who has taken
pains to place it at the farthest remove from his perch while still
(to avoid undesirable steps) on his daily track. If this be really its
object, it is surely one of the oddest devices in nature."
The curious winter cases of the Viceroy were first carefully described
by the late Dr. C. V. Riley, in one of his classic reports on the
insects of Missouri. It is one of the best accounts which has ever
been written and is well worth quoting at some length:
"The larvae of the autumnal brood," wrote Doctor Riley, "when about
one fourth or one third grown, build for themselves curious little
houses in which they pass the winter. First and foremost--with wise
forethought and being well aware through its natural instincts that
the leaf which it has collected for its house will fall to the ground
when the cold weather sets in unless it takes measures to prevent
this--the larva fastens the stem of the leaf with silken cables
securely to the twig from which it grows. It then gnaws off the blade
of the leaf at its tip end, leaving little else but the midrib.
Finally it rolls the remaining part of the blade of the leaf into a
cylinder, sewing the edges together with silk. The basal portion of
the cylinder is of course tapered to a point as the edges of the leaf
are nearly drawn together, not overlapped; and invariably the lower
side of the leaf forms the outside of the house so as to have the
projecting midrib out of the way of the larva as it reposes snugly on
the inside. The whole, when finished, has somewhat the appearance of
the leaf of a miniature pitcher-plant (_Sarracenia_), its length
being .50-.65 inch, and its diameter .11-.14 inch.
"These curious little cases may be commonly found upon our willows and
poplars in the winter time. I have examined hundreds of them and
although they are invariably built upon this plan, they vary greatly
in the degree of perfection which the architect attained; and this is
especially the case where they have been built in confinement. The
blade on the tip piece is sometimes gnawed off right down to the rib;
at others it is left almost as broad as the tube. Sometimes it is bent
over the orifice; at others not. They are also much more irregular and
ungainly when made with broad leaves, such as those of the silver
poplar, than when made from the more narrow leaves of the willow tree.
These autumnal larvae have also another peculiar habit: they exhibit a
tendency to build from the time they are hatched and will always eat
the leaves from the side, gnawing large holes and cutting along the
sides of the midrib. They commence at the tip, and as they work
downward toward the base, they collect the débris into a little bunch
which they fasten with silk to the midrib. When the hibernaculum is
finished the seam is perfectly smooth and the hole inside is lined
with silk. The larva, having completed its work, composes itself for
the winter with the hind end toward the orifice. Here it remains till
the catkins are in bloom the next spring when it retreats from its
house and commences feeding. Not the least wonderful part of this
phenomenon is that it is only the autumnal brood of larvae that form
pitcher-like houses to live in during the inclement season of the
year--the summer brood having no occasion to shelter themselves from
cold." It is an interesting fact that in most northern regions these
winter cases are nearly always made so near the ground that they are
protected by snow during most of the winter.
When an insect has such a curious habit as that of making these winter
cases it seems comparatively easy to explain it as an acquired
instinct brought about through the conditions of life during the long
period in which successive generations have been laid. But, as Doctor
Riley seems to suggest above, it is much more difficult to explain
this sort of phenomenon when it occurs only in one of two or more
broods during the season.
=The Banded Purple=
_Basilarchia arthemis_
None of our common butterflies shows more striking color markings than
the Banded Purple. A broad white stripe runs midway through the wings
on both surfaces, the white making a strong contrast to the purplish
or brownish black of the rest of the wings. This white band is
supplemented by rows of fulvous and of blue dots, especially on both
surfaces of the hind wings.
This butterfly is a northern form ranging to a large extent north of
the regions occupied by the Viceroy. Its life-history is very similar
to that of the latter insect. The caterpillars have the same curious
habits and bear a close general resemblance to one another. The Banded
Purple butterflies appear in June and lay their eggs in July upon the
tips of the leaves of birches, especially the black birch. Almost all
of these eggs are laid within two or three feet of the ground. They
are of grayish green color. The caterpillars are greenish- or
olive-brown.
About a week after the egg is laid it hatches into a small caterpillar
that feeds upon the sides of the leaf and rests upon the midrib just
as the Viceroy caterpillar does. It continues to feed through July and
the early part of August, moulting once or twice before it begins to
form the winter case. It usually goes into this during the latter part
of August, when it is in the second or third caterpillar stage. From
then on it remains quietly in its winter home, being covered by the
deep snows during several months, and coming out about the middle of
the following May, when the spring warmth starts the buds of its food
plant. It then feeds for two or three weeks before it changes to a
chrysalis to emerge in June as a butterfly. There seems to be normally
but one brood each year although under exceptional conditions some of
the eggs laid in July mature into butterflies the same season. But it
is probable that these butterflies either do not lay eggs and perish
as the cold comes on, or that if they do lay eggs the caterpillars
that hatch from them do not get large enough to construct their winter
cases. Consequently, it is doubtful if we can consider the insect
really two-brooded even in part.
=The Red-spotted Purple=
_Basilarchia astyanax_
Were it not for the wonderful iridescence of its wings the Red-spotted
Purple would be one of the most plainly marked of the Sovereigns. But
the upper surface of both pairs of wings is thickly covered with
iridescent scales which give the insect a shimmering beauty that makes
it conspicuous among northern butterflies, suggesting something of the
marvelous coloring of the large tropical species. The general coloring
is a purplish black with rows of white dots along the borders of the
wings. The under surface shows much more of the fulvous brown which is
so characteristic of the Viceroy, the brownish background being rather
thinly overlaid with iridescent scales, but with a large number of
spots and stripes, where the fulvous color alone shows.
The favorite food plants of this species belong to the great order
_Rosaceae_ which includes the apple, pear, cherry, rose, and many
other common trees and shrubs. The egg is laid upon the extreme tip of
the leaf, a characteristic habit of all the species of Basilarchia. It
obviously must have decided advantages in preserving the eggs from
attack by ants, spiders, Ichneumon flies, and other enemies. All of
these creatures are constantly patrolling leaf surfaces in search of
eggs and minute insects. They are much more likely to find their
victims upon the broad general surface than upon the extreme tip of
narrowly pointed leaves. The eggs of all these butterflies are small,
and pitted much like a tiny little honeycomb with a large number of
tiny hairs arising from the surface. These hairs are very similar to
the hairs upon the surface of many leaves and they probably assist in
leading other insects to overlook the eggs. Yet, notwithstanding these
devices for protection, it remains true that a large proportion of the
eggs are attacked by tiny parasites and probably many others are eaten
by ants and spiders. This very fact emphasizes the necessity of such
protective features as the laying of one egg in a place upon the tip
of a leaf and the hairy covering on the egg shells.
A few days after the eggs are laid each hatches into a small
caterpillar that immediately begins feeding upon the green tissues
beside it--first, however, devouring the empty egg shell. It does not
eat the midrib of the leaf, but utilizes it as a perch, generally
winding it more or less with silken threads, apparently to make it
stronger and to prevent it from curling up. The caterpillar seems to
feed chiefly at night, resting quietly by day. After a week or so it
moults and then continues feeding as before. It continues to feed and
grow for several weeks, moulting regularly until it becomes full fed
as a caterpillar. It then spins a web of silk closely upon the bark of
twig or branch or possibly upon some other object near at hand. In
this web it entangles the hooked claws of its hind legs and hangs
downward preparatory to the change to the chrysalis. Soon afterward
the last larval skin is shed and the chrysalis hangs in place of the
caterpillar. This chrysalis has the characteristic form of all the
members of this limited group, the outer skin being well hardened and
there being a very prominent projection on the middle of the back.
The chrysalis hangs thus, buffeted more or less by wind and rain for
about ten days, then the skin breaks apart and the butterfly emerges.
Over a large part of its range there are two broods of this butterfly
each year. The adults appear in early summer and lay eggs which
develop into butterflies again during the latter part of summer. The
life-history of this generation is the one described in the last
paragraph. The eggs laid by these late summer butterflies, however,
require a somewhat different story. They hatch in the same way as the
others but when the caterpillars have moulted about twice they form a
winter case or hibernaculum, in exactly the same way as the
caterpillars of the Viceroy. They remain within these winter homes
till the following spring, when they come forth and complete their
development producing the early summer brood of butterflies with which
our story began.
=The Vicereine=
_Basilarchia floridensis_
In Florida and some of the other Southern states there is a butterfly
which looks almost like the Viceroy except that the brown coloring of
the wings is very much darker. The species has been called the
Vicereine as it is believed to mimic the Queen Butterfly, a species
closely related to the Monarch and occurring in the Southern states.
The Vicereine probably has a life-history very similar to that of its
northern cousin.
_Synopsis of the Sovereigns_
_Banded Purple_ (_Basilarchia arthemis_ or _Limenitis arthemis_).
Expanse 2 1/2 inches. Ground color of upper surface of wings black
with a distinct white band in bow-like form running across the middle
of both wings. A row of six tawny spots just outside the white band on
each hind wing and various sub-marginal blue spots outside of these.
Under surface tawny brown with the white stripe distinct and many
red-brown spots.
_Red-spotted Purple_ (_Basilarchia astyanax_ or _Limenitis astyanax_).
Expanse 2 1/2 inches. Ground color brownish black tinged with bluish,
especially on the hind wings. No white band but various red and blue
spots, especially near the outer margins of the upper surface of both
pairs of wings.
_Viceroy_ (_Basilarchia archippus_ or _Limenitis disippus_). Expanse
2 1/2 inches. General color reddish brown with veins and margins
blackish. A narrow black band running across the hind wings just
beyond the middle. A series of white spots in all the marginal bands.
_Vicereine_ (_Basilarchia floridensis_). Expanse 2 1/2 inches. Similar
to the Viceroy but much darker in the brown coloring of all the wings.
THE TRIBE OF THE EMPERORS
The members of this small group are distinguished from the closely
related Sovereigns by the tailed hind wings in one species, by the
eye-spots on the upper surface of the wings of the others, and by the
fact that on the club of the antennae there are three instead of four
longitudinal ridges. There is also a distinction in the arrangement of
the veins of the hind wings.
This tribe is represented in our northern fauna by only two genera. In
the genus Chlorippe the antennae are as long as the front wings are
wide. In the genus Anoea the antennae are much shorter than the width
of the front wings. Only two species of the former and one of the
latter are sufficiently abundant to be considered here.
=The Goatweed Emperor=
_Anoea andria_
Comparatively few butterflies are confined so closely to the valley of
the Mississippi River as the Goatweed Emperor. From southern Illinois
south to the Gulf this insect is rather abundant in many localities
where its food plant, the goatweed, is common. The life-history of the
insect was carefully studied by Dr. C. V. Riley, and one of the best
accounts was published in one of his early reports on the insects of
Missouri. The excellent illustrations in that article first made the
species familiar to many students.
Briefly summarized, the life-history runs something like this: the
butterflies hibernate, coming forth in spring and visiting various
spring and early summer flowers. The females deposit eggs singly upon
the leaves of the young goatweed plants. In a week or less each egg
hatches into a little caterpillar that feeds upon the tip of the leaf
leaving the midrib and covering it with silk so that it may serve as a
resting perch. Later each makes an excellent tent for itself by
bending over and binding together the opposite margins of a leaf.[D]
This bit of work is cleverly done, a hole being left at each end so
that there is good ventilation and an opportunity for the caterpillar
to go in and out. Quite frequently the nest is also lined with more or
less silken webbing. This tent is used as a refuge from the heat of
the sun and doubtless serves also in concealing the caterpillar from
its many enemies. The larva goes out to neighboring leaves when it
wishes to feed and only occasionally eats up the leaf of which its
tent is made. When this is done it must of course construct another
home.
[D] _See next page._
[Illustration: THE BANDED PURPLE (_see page 202_)
THE RED-SPOTTED PURPLE (_see page 204_)
THE BLUE-EYED GRAYLING OR COMMON WOOD-NYMPH
(Upper and lower surface) (_see page 215_)]
[Illustration: _From drawings by W. I. Beecroft_
_See pages 207-214_
THREE EMPEROR BUTTERFLIES
The Gray Emperor, female (_top_)
The Tawny Emperor, female (_middle_)
The Goatweed Emperor, female (_bottom_)]
After some weeks of this sheltered existence the caterpillar is ready
to change to a chrysalis. It leaves the tent and commonly attaches a
bit of silken web to the under side of a leaf or branch of its food
plant or some other kind of shelter. Here it changes to a chrysalis,
to emerge a little later as the beautiful burnt-orange butterfly.
There are said to be two broods each season, in some regions, although
in others there seems to be but one. The butterflies hibernate in
hollow trees or in such other shelters as they may find.
[Illustration: Goatweed Butterfly: _a_, larva; _b_, chrysalis;
_c_, larval case. (After Riley)]
The full-grown caterpillar (_a_) is an inch and a half long and of a
general grayish color, dotted thickly with slightly elevated points.
The chrysalis (_b_) is suggestive of that of the Monarch butterfly.
It is light green covered with whitish granules.
The adult butterfly is remarkable for the falcate shape of the outer
margin of each front wing and the broad tail at the hind outer angle
of each hind wing. In the male the upper surface of all the wings is
of a dark orange tone, with a rather narrow brown marginal marking. In
the female this marginal band is broader and is nearly paralleled by
another narrower band a little nearer the body. In bright sunshine
there is a distinct purplish red iridescence over practically the
whole upper surface. The under side of both wings is of a color to
suggest a dead brown leaf, with a purplish iridescence in certain
angles of light.
=The Gray Emperor=
_Chlorippe celtis_
This very distinctive medium-sized butterfly is found in the Southern
states at least as far west as the Mississippi Valley. It extends
north to Indiana and Ohio and probably occurs quite generally from
Ohio eastward. This species is distinguished by the general gray-brown
or olive-brown coloring of the wing surfaces, heavily marked with a
much darker dusky brown and with many irregular white spots as well as
one large eye-spot on each front wing near the border, and a row of
seven more or less distinct eye-spots near the border of each hind
wing.
Like the Tawny Emperor this species feeds in the larval state upon the
leaves of hackberry. In Missouri the butterflies appear in June. A
little later they lay eggs upon the under side of the hackberry
leaves, commonly one in a place but sometimes several side by side. A
few days later these eggs hatch into little yellow caterpillars that
feed upon the leaves for about a month when they become full grown.
They are then a little more than an inch long, of a general light
green color with yellow spots along the middle of the back and three
yellow lines along each side. The head has a pair of curious antlers
much like those of the caterpillar of the Tawny Emperor. These
caterpillars now spin a bit of silken web on the under side of the
leaf or twig. They attach their hind legs into this web and hang
downward for a day or two, before casting the last larval skin and
changing to chrysalids. They change again to butterflies which are
seen upon the wing early in August. These butterflies lay eggs in turn
on the hackberry leaves, the eggs soon hatching into small
caterpillars which according to Riley's observations are less active
than those of the earlier brood. These caterpillars feed for a few
weeks until they become nearly half grown and have passed their second
or possibly their third moult. They now stop eating and get ready for
a long fast through the winter. Apparently some of them at least
attach themselves to the under side of the hackberry leaves and turn
to a brownish color, remaining upon the leaves until the latter fall
to the ground and presumably hibernating in the shelter thus provided.
Whether or not all of the caterpillars have this rather curious habit
seems to be doubtful. It has been suggested that some of them find
shelter within the crevices in the rough bark of the tree. At any
rate, the caterpillars remain in a sort of stupor until the following
spring. Then they awaken, climb up the trees or bushes, and begin
feeding upon the young leaves. They continue this until they become
full grown in May when they change to chrysalids, to emerge as the
first brood of butterflies the following month. Many of the
caterpillars make a sort of nest for themselves by spinning a web of
silk upon the under surface of the leaf and drawing together slightly
the outer edges.
As is the case with so many other butterflies that hibernate as
caterpillars, apparently the species is only partially double-brooded.
Some of the earlier caterpillars become lethargic when half grown and
remain in that condition throughout the later weeks of summer and all
through the fall and winter.
=The Tawny Emperor=
_Chlorippe clyton_
This handsome butterfly is easily distinguished from the Gray Emperor
by the general reddish color of the wings which are thickly marked
with bands and eye-spots of darker brown or black. The eye-spots are
especially marked on the hind wing, there being a row of five of these
on each hind wing in both sexes. The females are decidedly larger than
the male and generally of a distinctly lighter color.
This butterfly is a southern species found more or less abundantly
from southern New York to northern Florida and across the country to a
line drawn from Iowa to Texas. It seems to be more common in the
Mississippi Valley than in other regions and its life-history was
first thoroughly worked out in Missouri and published in one of
Riley's classic reports on the insects of that state. It has since
been studied by Edwards and others, but even now there seems to be
some uncertainty in regard to many points in its development, notably
the number of broods in different localities and the habits of the
larvae when preparing for hibernation.
The principal points in the life-history of the species may be
outlined as follows: some time in July the eggs are laid on the leaves
of hackberry in dense clusters, each of which may contain from two
hundred to five hundred eggs. These are usually deposited in two or
more layers, one upon another. A little more than a week later these
eggs hatch, each caterpillar eating through one end in a way to cut
out the rim of a tiny cap which is pushed up as the larva escapes. The
whole brood emerges at practically the same time and collects upon one
or more leaves where they begin to feed upon the succulent green
tissues. Like so many caterpillars that feed in companies each spins a
silken thread wherever it goes.
The little larvae remain together until after the third moult, at
which time they are about half grown. In the more northern regions
where they are found they are now likely to scatter about in search of
quarters for hibernation. Having found suitable shelter, they remain
through the winter to come forth early the following spring and feed
upon the developing leaves of the hackberry trees. They continue to do
this for a few weeks before they become full grown. They are then
smooth-bodied, greenish worms about an inch and a half long, striped
longitudinally in yellow and brown. The hind end of the body is forked
in a curious fashion and the head is even more remarkable for the
strange pair of tiny antlers projecting from it.
These full-grown caterpillars soon change to pale green chrysalids,
lightly striped with longitudinal lines of yellow, with a distinctly
pointed head. From these chrysalids butterflies emerge early in
summer.
Evidently in the more Southern states there are two broods of these
butterflies each year but there is great need of more precise
knowledge in regard to them.
As is the case with so many other butterflies there is a dimorphic
form, called _ocellata_, in which the outer half of the hind wing is
very dark brown, with the eye-spot showing as black with red-brown
circles.
_Synopsis of the Emperors_
_Goatweed Emperor_ (_Anoea andria_ or _Pyrrhanea andria_). Expanse
2 1/2 inches. Front outer angle of each front wing projecting into a
falcate tip. Rear outer angle of each hind wing projecting into a
distinct tail. General color burnt-orange with darker marginal bands,
and in the female on the upper surface other sub-marginal markings.
_Gray Emperor_ (_Chlorippe celtis_). Expanse 2 inches. General color
grayish brown with numerous markings of white and blackish. A distinct
brown eye-spot on the upper surface of each front wing near the outer
hind angle.
_Tawny Emperor_ (_Chlorippe clyton_). Expanse 2 inches. General color
tawny brown with markings of black and yellowish white. No distinct
eye-spot on upper surface of front wings.
THE MEADOW-BROWNS OR SATYRS
FAMILY _Agapetidae_
The Meadow-browns form one of the most distinctive family groups among
all the butterfly tribes. They are characterized, at least so far as
our eastern species are concerned, by their slender bodies and rather
large wings, toned in various shades of brown, and marked chiefly with
conspicuous and characteristic eye-spots. The larger veins of the
front wings are swollen at the base. The caterpillars are rather
slender and have a curious division of the last body segment into two
parts, which gives them an appearance suggestive of the caterpillar of
the Emperor butterflies, although the Meadow-brown caterpillars do not
have, upon the head, the curious antlers borne by the Emperor larvae.
=The Common Wood-nymph or Grayling=
_Cercyonis alope_
In the development of our knowledge of both birds and mammals as found
upon the American continent the experience in many cases has been
essentially this: a bird or a mammal was first described from some
well-known region of North America, commonly from specimens carried to
Europe by early voyagers. Later other species of the same genus were
brought to light by various explorers and given specific names. As
each section was thus explored a new form differing markedly from the
others was found and named. At a later period, when great collections
were brought together so that one observer was able to make a careful
survey of specimens from all parts of the continent, it was found that
many of these species merged into each other through intergrading
forms from regions between the localities of the original species. So
it has come about that in the case of a large number of our birds and
mammals we have geographical races distinctly recognized instead of
separate species.
While the study of butterflies has by no means received the degree of
attention which has been given the birds and mammals, it is already
evident that a similar condition prevails with reference to many
species. As the size of collections has increased and more careful
studies have been made of the various forms from different regions it
has been found in numerous cases that they intergraded to so great an
extent that it is impossible to distinguish many species which were
formerly considered entirely distinct. One of the most striking
examples of this is found in the case of our common Wood-nymph, which
is sometimes called the Blue-eyed Grayling. The form which is one of
our most abundant butterflies in southern New England and many of the
Eastern states was described as _Satyrus alope_ by the French
naturalist Fabricius, who also described another species from the
Southern states as _Satyrus pegala_, and a form found in northern
Canada was described by the English entomologist Kirby as _Satyrus
nephele_. Various other forms from isolated regions have been given
specific names by other authorities. (_See plate, page 81._)
During recent years many collectors have gathered these butterflies
from all parts of North America and many specimens have been grouped
together in the more important collections. When this occurred it
became easy to see that this is essentially a variable species which
under varying climatic conditions has assumed slightly different
forms, so that we have a good illustration of well-developed
geographical races. The more important of these are indicated in the
synopsis of the Meadow-browns on page 227.
_The Similar Life-histories_
One good indication that these varying forms all have a common origin
is found in the remarkable unity of their life-histories. It is
essentially the same in all. The mother butterflies lay eggs late in
summer upon the leaves of grasses and perhaps other plants. About
three weeks later these eggs hatch into small caterpillars that
immediately become lethargic and begin their hibernating condition
without eating any vegetation. They remain thus fasting until spring
when, after the weather warms up sufficiently, they begin to feed upon
grasses and perhaps other herbage. But they have lots of time in which
to complete their growth and they are very moderate in their eating
and their movements. They grow slowly so that they do not become
mature as caterpillars until June. They then change to chrysalids to
emerge as butterflies during July and August. The female butterflies
remain upon the wing for some weeks before they begin to lay their
eggs. We thus have in this case an adaptation to single-broodedness in
practically all stages of the insect's life. The twelve months of the
year must be passed and egg, larva, chrysalis, and butterfly each
seems to try to do its part in prolonging its period of life.
These butterflies are especially common along streams and near the
borders of woods, as well as in upland pastures and meadows. They are
interesting creatures with characteristic manner of flight. They are
by no means so easy to capture as one might think who sees them
apparently going with slow, erratic motions from flower to flower. Mr.
S. F. Denton, a collector of long experience, has written this
interesting paragraph upon this point:
"As the flight of these insects is weak, they have been obliged to
resort to a number of tricks to outwit their enemies. In capturing
these butterflies the collector will very soon become acquainted with
their modes of escape, which are very interesting and show no small
amount of cunning, scarcely to be looked for in an innocent little
butterfly. Their first plan of escape on being disturbed is to make
directly for a clump of bushes into the thickest part of which they
dive and there remain until the danger is past. If one is startled
from the grass at some distance from a safe retreat and the collector
overtakes him, he will immediately dodge backward and forward, at one
time high in air and again low down near the grass tops, and in spite
of his slow flight keeping well clear of the net. If the net is at
last brought very close to him he will try his last desperate scheme
to elude his pursuer and shutting his wings quickly together will drop
into the grass, disappearing as if by magic. If it were not for the
cunning of the frail little creatures they would doubtless have gone
to the wall long ago in the struggle for existence."
=The Southern Wood-nymph=
_Cercyonis pegala_
This large southern butterfly is sufficiently distinct from the other
Wood-nymphs to rank as a separate species. The yellow blotch has
expanded into a large band extending practically across the front
wings. On its upper surface there is one eye-spot in the male and two
in the female. It is abundant in the extreme Southern states and has
occasionally been taken much farther north.
=The Pearly Eye=
_Enodia portlandia_
Most butterflies are creatures of open country, basking freely in the
sunshine and visiting flowers of many sorts for their nectar food.
Some of them are found at times along the borders of woods and others
seek the woods especially in autumn for the purpose of hibernation.
This exquisite Pearly Eye, however, is distinctly a woodland species,
being found only in little glades in the midst of woods and apparently
seldom even seeking flowers for their nectar. It is commonly
considered one of the rarest of American butterflies, but many
collectors who have searched their regions carefully have been able to
find small areas in which the butterfly is quite abundant. In such
situations it may be looked for in all parts of the United States east
of the western limits of the Mississippi Valley and south of Canada,
except perhaps the lower part of Florida.
In northern regions this butterfly is single-brooded: the adults
appear shortly before midsummer and continue on the wing through July
and at least part of August. The eggs are laid some weeks after the
butterflies emerge. The caterpillars feed upon grasses and apparently
hibernate after they become well grown, changing to chrysalids the
following spring in time to emerge as butterflies in early summer.
These Pearly Eyes have certain characteristics which are of especial
interest. No other species presents such exquisite modulation of brown
coloring arranged in beautiful circles upon both surfaces of the
wings. The males possess, perhaps to a greater degree than any other
of our native butterflies, the ability to give off a peculiar,
pleasant aroma which is noticeable whenever the insects are collected
and which at least one careful observer has been able to detect in the
open air as the butterfly flew near.
For many years Mr. W. F. Fiske made a special study of the butterflies
prevailing in the region of Webster, New Hampshire. His word picture
of the haunts of the Pearly Eye is more adequate than any other which
has been published and seems well worth quoting in this connection:
"I have found them in several localities, always in some numbers, but
nowhere more abundant than in a little wooded glen in Webster. Here a
scattering group of tall pines, a few thick hemlocks, and a young
growth of miscellaneous deciduous trees fill up the space between two
rather steep banks. A small trout brook follows close by one of these
banks, and near the lower end of the glen, in a space kept clear of
underbrush by the overshadowing influence of the pines and hemlocks,
is a little spring, the overflow from which keeps the ground moist for
some space on each side of the channel which it follows to the brook.
This is the great meeting place of these butterflies; here they may be
seen at almost any time in the day except in the early morning--when
they seek the outskirts of the woods--until the shades of evening
render their flitting forms indistinguishable. Half-way up the bank on
one side, half shrouded in the dense growth of underbrush which is
springing up around it, is an old apple tree upon which the sapsuckers
work yearly. The wounded limbs, dripping with sap, are frequented by
many forms of insect life, most noticeable among them this butterfly,
and such refreshment added to the moisture which they suck from the
margin of the spring is all that I have ever seen them partake."
=The Eyed Brown=
_Satyrodes canthus_
For delicacy of gray-brown color tones few butterflies can compare
with this exquisite creature. It seems indeed to have succeeded in a
modest attempt to obliterate itself, for even when the spread wings
are placed against a clear white background they can scarcely be
called conspicuous and it is very probable that when the butterfly is
at rest in its native haunts, with wings closed together so that only
the very delicate light brown color-tones of the under surface are
revealed, it actually becomes invisible.
The upper surface of the wings is broadly washed with a gray-brown
color which runs into a suggestion of a lighter band near the outer
margin of the front pair. The upper surface of the hind wings is
almost uniformly washed with this same brown color which is
interrupted only by very fine, double lines at the outer margin and a
sub-marginal row of delicate _ocelli_ which are larger than the
somewhat similar sub-marginal row of eye-spots on the front wings. The
under surface is much lighter in color, with distinct striations
extending across the main surface of both wings from front to back and
with some very attractive _ocelli_ arranged as a sub-marginal series
each with a central white eye.
This is distinctly a northern species, having rather a limited range
in Canada and New England. It extends south to Pennsylvania and Ohio
and westward to Wisconsin and Iowa. It is more abundant in northern
than in southern New England but it is often overlooked by collectors
who are not familiar with its haunts. It is especially likely to be
found among the tall grass of swamps and brooks running through
lowlands. One of the best ways to discover it is to beat the grasses
in such situations.
The life-history of the Eyed Brown is fairly well known. The eggs are
laid chiefly on grasses and probably at times upon the grass-like
sedges. The larvae feed upon these plants and become nearly full grown
before winter sets in. They then hibernate in this larval stage and
the following spring complete their growth and change to chrysalids in
time for the butterflies to emerge in June. There is but one brood a
year.
=The White Mountain Butterfly=
_Oeneis norna semidea_
To appreciate the extraordinary distribution of this notable species
one must let his fancy carry him back a million years or so until he
reaches that old time when the whole northern part of the American
continent was covered with an icy coating. Then he must follow the
gradual retreating of the ice northward, carrying with it wonderful
changes in climate and along with these climatic changes taking
northward many plants and animals which were adapted to the cool
temperature along the borders of the glacier. As the ice cap retreated
most of these arctic forms retreated with it, and all along the lower
levels they were replaced by others migrating from the south so that
gradually there came about the distribution of plants and animals as
we find them to-day.
When, however, the glaciers left the higher elevations of the White
Mountains and the Rocky Mountains there were at the summits small
areas in which the climatic conditions were of very much the same
arctic character as prevailed along the margin of the ice cap.
Consequently conditions were here favorable for the continuation of
many of the arctic species which had disappeared from the warmer,
lower levels. It was as if we had a great sea of air of a certain
warmth and rising above this the islands of the mountain tops, these
islands retaining the same arctic features as otherwise are found much
farther northward.
Among the animals thus left stranded by the retreating ice cap this
White Mountain butterfly has perhaps attracted the most attention from
scientists. It is a butterfly of moderate size which shows in every
phase of its structure and its life-history the results of the long
process of adaptation to its unique environment. It has been carefully
studied by many observers and has been considered one of the most
desirable trophies by every collector of insects. As a result,
notwithstanding its isolation and the difficulty of studying it, its
life-history is better known than that of many a common and widely
distributed species.
To appreciate the facts in regard to the structure and life of this
butterfly one must know that its habitat is confined to a thousand
feet or so at the summits of the mountain, that in this area there are
no trees or even shrubs worth mentioning, and that the surface of the
mountain is covered with rocks between which grow a few stunted sedges
and over which grows the ever-present reindeer moss. It is a bleak,
bare, gray environment, constantly swept by terrific winds, where snow
is seen in August and is likely to remain until June. So the summer
season is of briefest duration and the climatic conditions are so
severe that one can only wonder how a fragile creature like a
butterfly is able to survive the twelve long months.
_Habits and Life-history_
From a first glance at the mottled gray-brown wings of these insects
one would guess that here was a distinctive example of obliterative
coloring, and it is true as all observers testify that when the
butterfly lights upon the stones and turns sideways, as apparently it
does habitually in deference to the force of the wind, it becomes very
difficult to see, for the wings are closed and only the rounded,
mottled under surface shows. It appears also to have the habit of some
of the Graylings when hard pushed of simply closing its wings and
dropping to the ground feigning death. In deference also to the winds
its flight is just above the surface. Doubtless if it rose high in the
air it would be swept away to lower regions where evidently it is
unable to survive for long periods.
[Illustration: _From a drawing by Mary E. Walker_ _See page 229_
THE ZEBRA BUTTERFLY
On orange leaves and blossoms. (Reduced)]
[Illustration: On a milkweed pod]
[Illustration: _From "Seeing Nature First"_ _See pages 47, 235_
On clematis seed-fruits
PHOTOGRAPHS OF A PET MONARCH BUTTERFLY]
These butterflies appear early in July and continue on the wing for
several weeks. They lay their small eggs upon or near a species of
sedge which is abundant on these alpine summits. About two weeks later
the eggs hatch into sluggish little caterpillars which feed upon the
sedge leaves, apparently eating only at night and hiding in crevices
between stones by day. As one would expect from the prevailing low
temperatures these caterpillars grow very slowly and apparently a
large proportion of them require two years to complete their
development. There seems to be some uncertainty in regard to this
phase of the insect's life-history, but most entomologists are of the
opinion that some of the butterflies mature in one year while others
require two years: that is, the broods are both annual and biennial.
There is no doubt that the insect hibernates as a caterpillar, and if
this statement about the number of broods is correct some of the
caterpillars hibernate when very small, and recently hatched from the
egg, while others hibernate when nearly full grown.
The full-grown caterpillars change to chrysalids beneath the shelter
of the small stones in practically the same sorts of situation which
they have chosen for hiding at night or for hibernation through the
winter. Here without any button of silk or silken loop and with
scarcely a suggestion of a silken cocoon they change to chrysalids,
generally about the first of June. They remain in this condition for
perhaps three or four weeks when they come forth as butterflies.
=The Arctic Satyr=
_Oeneis norna jutta_
This is another butterfly of decided interest because of its
geographical distribution. It is normally an inhabitant of the Far
North, extending around the North Pole over parts of three continents.
Apparently, the only place in the United States where it occurs is a
bog a little north of Bangor, Maine. This locality is called the
Orono-Stillwater bog and is the only place where collectors have been
able to find this species.
* * * * *
An even more local insect is another of these mountain butterflies
found by H. H. Newcomb on Mount Katahdin, Maine. So far as known this
species is confined to the higher portion of this mountain and so is
even more distinctly localized than the White Mountain butterfly. It
is called the Katahdin butterfly (_Oeneis norna katahdin_).
=The Little Wood Satyr=
_Cissia eurytus_
This elfin creature has well been named the Little Wood Satyr,
although under our modern conditions it is often found in fields and
along hedgeroads rather than in the woods. It has, to a marked degree,
the delicacy of structure of its allies and its small size serves to
emphasize this appearance. It has also a rather general distribution
west to the Mississippi Valley, extending from the corner of Dakota,
south through Nebraska, Kansas, and central Texas, and north to
Wisconsin, Michigan, and New England. It occupies the whole of the
United States east and south of the lines thus indicated.
The life-history of this species is very similar to the Common
Grayling. The butterflies appear in early summer, deposit their eggs
upon grasses, and the resulting larvae feed upon the grasses and grow
slowly through the weeks of summer. They become nearly full grown by
autumn and hibernate in this condition in such shelter as they can
find at the soil surface. The following spring they come forth,
probably feeding for a short time, and change to chrysalids in time to
emerge as butterflies in May and early June. Practically all observers
emphasize the fact that the butterflies are abundant only late in
spring or early in summer, generally disappearing before the middle of
July. There is thus but one brood a year.
_Other Meadow-browns_
The _Gemmed Brown_ (_Neonympha gemma_) is a small southern species
remarkable for the plainness of its gray-brown wings which are marked
on the upper surface only with two or three dark spots on the middle
margin of each hind wing. There are two broods a year.
The _Georgia Satyr_ (_Neonympha phocion_) is another small southern
form, remarkable for the four elongated eye-spots on the lower surface
of each hind wing. The shape of these spots distinguishes it at once
from the _Carolina Satyr_ (_Cissia sosybius_) in which the eye-spots
are rounded.
_Synopsis of Meadow-browns_
_Pearly Eye_ (_Enodia portlandia_ or _Debis portlandia_). Expanse
2 1/4 inches. Eyes hairy. Outer margin of hind wings projecting in a
noticeable angle. Brown with many distinct eye-spots on both surfaces
of wings.
_Eyed Brown_ (_Satyrodes canthus_ or _Neonympha canthus_). Expanse 2
inches. Eyes hairy. Margin of hind wings rounded, without an angle.
Both surfaces of wings pale brown with four distinct blackish
eye-spots on each front wing near the margin. Five or six such spots
on each hind wing.
_Common Wood-nymph_ or _Grayling_ (_Cercyonis alope_). Expanse 2
inches. Eyes not hairy. Eye-spots on front wings, but not on upper
surface of hind wings. The chief geographical races of this abundant
species are indicated below, although in regions where the forms
overlap many intermediate hybrids occur.
_Blue-eyed Grayling_ (_Cercyonis alope alope_). A large
yellowish-brown blotch near outer margin of each front wing, above and
below, with two distinct eye-spots in middle spaces of the blotch. A
southern race extending north to central New Hampshire, Michigan, and
Wisconsin.
_Dull-eyed Grayling_ (_Cercyonis alope nephele_). The yellowish brown
blotch obsolete or nearly so, but eye-spots present. A northern race
extending southward only to central New Hampshire, Michigan, and
Wisconsin.
_Maritime Grayling_ (_Cercyonis alope maritima_). Similar to the type
form, but with the yellowish blotch tinged with reddish. A race found
only near the seacoast.
_Southern Wood-nymph_ (_Cercyonis pegala_). Expanse 3 inches. Eyes not
hairy. General color brown with an orange-yellow blotch near outer
margin of each front wing above and below with one eye-spot in middle
space of the blotch on the male, and two on the female.
_Little Wood-satyr_ (_Cissia eurytus_ or _Neonympha eurytus_). Expanse
1 1/2 inches. Eyes not hairy. General color fawn-brown with two
eye-spots on upper surface of each front wing and several on each hind
wing.
_Gemmed Brown_ (_Neonympha gemma_). Expanse 1 1/4 inches. Eyes not
hairy. General color mouse-brown with no markings on upper wing
surface except a rather indistinct pair or more of spots next the
margin of the middle of each hind wing. Under surface indistinctly
striped with rusty lines and a few brown and silvery spots on the hind
wings directly beneath the spots on the upper surfaces. Occurs in
Southern states.
_Georgia Satyr_ (_Neonympha phocion_). Expanse 1 1/4 inches.
Distinguished from the related species by the four distinct eye-spots
on lower surface of each hind wing, these spots being transversely
elongated rather than round. Occurs in Southern states.
_Carolina Satyr_ (_Cissia sosybius_). Expanse 1 1/4 inches.
Distinguished by the row of round eye-spots near outer margins of
lower wing surface. Occurs in Southern states.
THE HELICONIANS
FAMILY _Heliconidae_
This is a tropical family with only a single species migrating
northward to our Southern states. The butterflies of this group are
characterized by having the wings so long and narrow that their length
is usually twice as great as their width. The front legs in both sexes
are so poorly developed that they are considered a modification
approaching the complete dwarfing found in the Brush-footed
butterflies.
=The Zebra Butterfly=
_Heliconius Charitonius_
While the butterflies of temperate North America show many examples of
marvelous beauty and coloring, one must go to the tropics to see the
culmination of what nature has done in painting the outstretched
membranes of butterfly wings with gorgeous colors. The great butterfly
tribes that swarm in tropical forests seldom reach our temperate
clime, and even when they do they are likely to show only a suggestion
of the splendid size and rich coloring to be seen farther south. The
Zebra butterfly (_Heliconius charitonius_) belongs to one of these
tropical tribes. It shows its affinities by its coloring and the
curious shape of its wings. In most of our northern butterflies, the
wings are about as long as they are wide, but in the tropical family,
_Heliconidae_, they are very much longer than wide. This gives the
insect an entirely different look from our common forms so that one
recognizes it at once as a stranger within our gates. Indeed, it does
not penetrate far into our region, being found commonly only in
Florida and one or two other neighboring states, its principal home
being in tropical America.
The Zebra butterfly is well named. Across the brownish black wings
there runs a series of yellow stripes, three on each front wing and
one on each hind wing, with a sub-marginal row of white spots on each
of the latter. The under surface is much like the upper, except that
the coloring is distinctly paler. It is very variable in size: some
specimens may be but two and a half inches across the expanded wings,
while others are four inches. (_See plate, page 224._)
The Zebra caterpillars feed upon the leaves of the passion flower.
When full grown they are about an inch and a half long, whitish, more
or less marked with brownish black spots arranged in transverse rows,
and partially covered with longitudinal rows of barbed black spines.
They change to chrysalids which are remarkable for their irregular
shape, with two leaf-like projections on the head which the insect can
move in a most curious fashion.
One of the most notable things about this insect is the fact that the
male butterflies are attracted to the chrysalids of the females even
before the latter emerge. Many observers have reported upon this
curious phenomenon and have recorded experiments demonstrating that it
is a general habit with the species.
_The Roosting Habits_
The adult butterflies flock together at night and rest upon the
Spanish moss which festoons so many of the trees in the Far South, or
upon dead branches. They take positions with heads upward and wings
closed, many of them often flocking together to roost, and wandering
out to the near-by fields when the morning sun gives them renewed
activity. But these butterflies are essentially forest insects.
Reliable observers have noticed that when one emerges from a chrysalis
it flies up in the air and makes straight for the nearest woods.
Others have noticed that when a butterfly in a field is alarmed it
also makes for the woods. And in the regions where the species is
abundant the butterflies are most likely to be found in paths and
glades in the forest. Thus they show the influence of their ancestral
habitat in the tropical wilderness.
There seems to be a certain amount of ceremony attending the flocking
together at night for roosting purposes. A famous English naturalist,
Philip Henry Gosse, saw the performance in the West Indies many years
ago and described it in these words:
"Passing along a rocky foot-path on a steep wooded mountain side, in
the Parish of St. Elizabeth (Jamaica), about the end of August, 1845,
my attention was attracted, just before sunset, by a swarm of these
butterflies in a sort of rocky recess, overhung by trees and creepers.
They were about twenty in number, and were dancing to and fro, exactly
in the manner of gnats, or as _Hepioli_ play at the side of a wood.
After watching them awhile, I noticed that some of them were resting
with closed wings at the extremities of one or two depending vines.
One after another fluttered from the group of dancers to the reposing
squadron, and alighted close to the others, so that at length, when
only two or three of the fliers were left, the rest were collected in
groups of half a dozen each, so close together that each group might
have been grasped in the hand. When once one had alighted, it did not
in general fly again, but a new-comer, fluttering at the group,
seeking to find a place, sometimes disturbed one recently settled,
when the wings were thrown open, and one or two flew up again. As
there were no leaves on the hanging stalks, the appearance presented
by these beautiful butterflies, so crowded together, their long, erect
wings pointing in different directions, was not a little curious. I
was told by persons residing near that every evening they thus
assembled, and that I had not seen a third part of the numbers often
collected in that spot."
THE MILKWEED BUTTERFLIES
FAMILY _Lymnadidae_
So far as the great majority of readers of this book are concerned,
this family includes but one species--the familiar Monarch or Milkweed
butterfly. In the Southern states there is another--the Queen--and in
Florida, still a third. The distinguishing characteristics are found
in the dwarfed, useless front legs and the absence of scales upon the
antennae.
=The Monarch=
_Anosia plexippus_
From June until October one may often see the stately Monarch flitting
leisurely about over fields and meadows. It is one of the largest and
most distinctive of these "frail children of the air" and may be
easily recognized by its resemblance to the picture opposite page 241.
The veins of the wings are heavily marked in black, with large white
dots upon the black bands along the margin. The color of the rest of
the wings both above and below is reddish brown.
These butterflies come from the South in spring or early summer. They
find milkweed plants and lay their eggs upon the leaves. These eggs
soon hatch into small white and black caterpillars that feed upon the
milkweed leaves and grow rapidly. One is likely to find them
throughout most of the summer, wherever a milkweed shows partially
eaten leaves. Bring in the half-grown caterpillars, place them in an
open vivarium, and furnish fresh leaves every day or two. The
caterpillars will soon mature and change to beautiful green chrysalids
with golden markings. This chrysalis has been called "the glass house
with the gold nails." (_See plates, pages 32-33, 241._)
About two weeks later the glass house will burst open and the
butterfly emerge. It will rest an hour or two while its wings and body
harden and then it will want to fly away. It is not so anxious to do
this, however, as most butterflies. If one is kept beneath a
good-sized bell-glass, or in a glass-covered box, or even in a closed
room, and fed with sweetened water it will soon become so tame that it
will perch on one's finger and suck nectar from a flower held in one's
hand. On this account it is a particularly desirable butterfly for the
amateur photographer to cultivate, because he can easily get many
interesting and beautiful pictures by posing the butterfly on
different flowers.
_The Change from Caterpillar to Butterfly_
The change from the caterpillar to the butterfly is easier to watch in
this species than in most others. The full-grown caterpillar
spins--sometimes on the under surface of the milkweed leaf, sometimes
elsewhere--a little mat of silk in which it entangles the hooked claws
of its hind feet. Then it lets go with its fore feet, and hangs
downward with the front end of its body curled upward. In this
position it remains for some hours--perhaps a day--the body juices
gravitating downward and causing a swollen appearance on the lower
segments. Then the skin splits apart and is wriggled off by the
contortions of the body. When it finally drops away, there is left a
strange-looking creature, broader below than above. This is a
transition stage that lasts but a very short time: soon the form is
entirely changed so that the broadest part is above instead of below.
The definite outline of the chrysalis is soon taken on, the outer
tissues hardening into a distinct covering. The insect is now a
beautiful green with wonderful golden spots upon its surface and a few
black spots just below the black "cremaster" by which the chrysalis is
connected with the web of silk upon the leaf.
In this quiet chrysalis the insect remains for nearly a fortnight.
Then the structure of the forthcoming butterfly begins to show through
the thin outer covering and you know that the period of the chrysalis
is nearly ended. If you keep watch you will probably see the sudden
bursting of the outer envelope and the quick grasping of its surface
by the legs of the newly emerged butterfly. Its wings at first are
short and crumpled, bearing little resemblance to those of the fully
developed butterfly. But as it hangs there with one pair of legs
holding to the empty chrysalis and the other to the leaf above, the
wings rapidly lengthen, hanging limply downward, and the body juices
penetrate the veins. A little later they expand in the other
direction, the hind wings reaching full size before the front ones do.
Finally both pairs of wings are fully expanded, and the butterfly is
likely to walk to the top of the support, where it rests for an hour
or two while its tissues harden, before it attempts to fly.
In early autumn out of doors these butterflies start southward on
their long journey. They often gather in great flocks and roost at
night on wayside shrubs and trees. At this season it is easy to catch
them in an insect net and bring them indoors for pets. They live for a
long while and lend interest and beauty to living room or window
garden. To the photographer they offer opportunities for attractive
indoor pictures. (_See plates, pages 32-33, 160, 225._)
=The Queen=
_Anosia berenice_
The general form and color patterns of this fine butterfly show at
once that it is related to the Monarch. Its general colors are
chocolate-brown and black, dotted and spotted with white. The eggs are
laid upon milkweed and the life-history is much like that of the
Monarch. One of the most interesting facts in connection with this
species is that it seems to be mimicked by the Vicereine butterfly in
the same way that the Monarch is mimicked by the Viceroy.
THE SNOUT BUTTERFLIES OR LONG-BEAKS
FAMILY _Libytheidae_
One has a suggestion of Hobson's choice in the common names of this
unique family. If Snout butterflies does not seem sufficiently elegant
as a descriptive phrase for such delicate creatures, he can call them
the Long-beaks, until he sees that this also is inadequate. As a
matter of fact both are misnomers, for the projection from the head
that gives them these names is neither a snout nor a beak. It is
simply a pair of palpi unusually developed, which perhaps in an early
stage of butterfly history served a useful purpose. At present,
however, they serve chiefly to set the few owners apart from the other
butterflies in the system of classification; although possibly they
may also serve the butterfly by helping to give the impression of a
leaf attached to a twig. (_See plate, page 240._)
=The Snout Butterfly=
_Hypatus bachmani_
There is a peculiar interest in any form of animal life which can be
definitely traced far back through the geologic ages. In nearly every
group of living creatures there are certain types which scientists
have found were once abundant but which now are on the wane. As a rule
these are better represented in the museums through fossil species
than by those now living. To a considerable extent also such forms are
likely to present various features which mark their primitive
condition and the living allies have peculiarities which set them off
as distinct from those of their own relations which have been modeled
in a more modern fashion. Among the mammals the curious marsupials, of
which our southern opossum is an example, furnish good illustrations
of this general truth. Among the birds the curious little Least
Bittern is an example. Among the butterflies the strange Snout
butterfly is by far the best example.
These Snout butterflies, of which only two species are now living in
North America, are the sole representatives with us of the family
_Libytheidae_ or the Long-beaks. Only one of these species occurs to
any extent at least north of Texas. It is the curious little creature
called the Snout butterfly. It has a strange appearance due to the
angular outline of both front and hind wings and the long palpi which
project forward from the head in a way to attract attention. The
common name is due to these projecting palpi. Even the coloring is
primitive, the general tone of the wings being blackish brown,
distinctly marked with white and orange spots. The under surface is
less primitive in its coloring, being toned in iridescent grayish
brown in a way to suggest protective coloring, except in that part of
each front wing which is not hidden when the insect is at rest. This
shows the white and orange-brown markings.
Some years ago there were found in certain fossil deposits in the
West about a dozen species of fossil butterflies. It is strange indeed
that these ethereal creatures should be fossilized at all. One would
think it scarcely possible that they could be so preserved that a
million years after they had died man should be able to study them,
determine to what families they belonged, and even guess with a high
probability of accuracy upon what leaves their caterpillars fed. This
little collection of fossil butterflies was studied by one of the
great American authorities on living butterflies, the late Samuel H.
Scudder, who said of them: "They are generally preserved in such fair
condition that the course of the nervures and the color patterns of
the wings can be determined, and even, in one case, the scales may be
studied. As a rule, they are so well preserved that we may feel nearly
as confident concerning their affinities with those now living as if
we had pinned specimens to examine; and, generally speaking, the older
they are the better they are preserved."
A curious fact is that out of the comparatively few species of these
fossil butterflies two were easily recognized as members of this
Long-beak family. They were given special scientific names and
undoubtedly were closely related to the Snout butterfly which is still
flying every year in various parts of the United States. Our modern
species lays its eggs upon the leaves of hackberry and in these
geologic deposits of that far-gone era there have been found
well-preserved leaves of old hackberry trees, upon which it is
extremely probable that the caterpillars of these ancient Long-beaks
fed. What an opportunity for a modern collector of butterflies to work
his fancy, as he thinks of those old times when these fossil creatures
were flying in the sunshine, depositing their eggs upon the leaves of
trees that made up landscape pictures probably very different from
those of to-day! And how he wonders what flowers these butterflies
visited for their nectar food, what birds chased them from tree to
tree, and what mammals wandered through those ancient forests. What a
suggestion also it gives of the continuity of life upon our old earth
to realize that these butterflies of to-day are carrying on their
brief existence in practically the same way that these forbears of
theirs did so many millions of years ago.
Another way in which these butterflies are peculiar is the fact that
the females have six well-developed legs while the males have only
four. As already indicated the caterpillars feed upon hackberry. When
full grown they are about an inch long, dark green, striped with
yellow, with two blackish tubercules on the second ring behind the
head. They apparently pass the winter in the chrysalis stage. The
butterflies are likely to be found along the borders of brooks or
streams running through woods, or along the margins of the forest.
Occasionally they become abundant in certain localities, but on the
whole they are rare and highly prized by collectors.
THE METAL-MARKS
FAMILY _Riodinidae_
This small family of very small butterflies contains five genera and a
dozen species found in the United States and Mexico. Only two,
however, occur in the eastern region and only one extends much north
of the Gulf states. Aside from certain peculiarities of the
wing-venation (a costal and a humeral vein on the hind wings) these
Metal-marks may be known by their minuteness and the bright metallic
markings on the brown wings.
Both our eastern species belong to the genus _Calephelis_. The Small
Metal-mark (_C. caenius_) has been collected in Florida and Georgia.
The wings are rusty red on both surfaces, brighter below than above,
and marked with blackish spots that almost converge to form stripes;
in addition to which there are, beyond the middle of each wing, two
lines made by special scales that glisten with a steel glitter. The
wings expand only about three quarters of an inch. So far as I can
learn, the egg, larva, or pupa have never been described.
The Large Metal-mark is called by science _Calephelis borealis_, but
it deserves the latter name only in the sense that it is more northern
than its allies. It has been collected as far north as New York and
Michigan, but it seems to be very seldom found, at least in eastern
regions. It expands a little more than an inch. The general color of
the wings is yellowish brown, marked with blackish dots and lines,
together with rows of steely spots on the under surface. In this case
also the life-history is unknown.
[Illustration: _See page 236_
THE SNOUT BUTTERFLY IN FLIGHT AND AT REST]
[Illustration: _See page 62_
GIANT SWALLOWTAIL JUST OUT OF THE CHRYSALIS]
[Illustration: _From a drawing by W. I. Beecroft_ _See page 233_
THE MONARCH BUTTERFLY
Caterpillar feeding; caterpillar hung up for pupation;
chrysalis, and adult]
THE GOSSAMER-WINGS
FAMILY _Lycaenidae_
The daintiest and most delicate of all our butterflies are included
among the Gossamer-wings. Their bodies are small and slender, their
antennae ringed with white and almost threadlike, their wings thin and
of exquisite beauty. Many of them are marked with the slenderest of
tailed projections from the hind wings. When the face is viewed
from in front it is seen to be much narrower than its height. At the
insertion of the antennae the eyes are notched, and they are also more
or less surrounded with white scales. Most of the caterpillars have
oval, slug-shaped, smooth bodies, with the under surface flattened,
and very small heads, which in many species can be extended by means
of an extensile neck. The chrysalids are held in place by silken
threads both at the tail and over the middle. They are rounded, short,
and stout.
Notwithstanding their small size, the Gossamer-wings are among the
most spritely of all our butterflies. They seem indeed winged sprites,
playing everywhere, in fields and open woods, along roads, lanes, and
brooks, in dooryards and gardens--wherever, in fact, a bit of open
space invites their presence. Not alone upon the wing but even when at
rest does their liveliness appear. For most of these butterflies have
the curious habit of keeping the hind wings in motion after alighting,
rubbing them against each other in a vertical plane or "moving them
backward and forward when half expanded." These habits are so fixed
that when one sees a butterfly thus engaged one can pretty certainly
conclude it is a member of this family.
The Gossamer-wings are commonly separated into three rather distinct
tribes--the Hair-streaks, the Coppers, and the Blues. The
characteristic features are these:
Three branches arising from the radius of each front wing. Under
surface of hind wing commonly marked with threadlike streaks: the
Hair-streaks.
Four branches arising from the radius of each front wing. Under
surface of hind wing commonly marked with spots rather than lines.
Colors brownish red: The Coppers.
Colors blue: The Blues.
THE TRIBE OF THE HAIR-STREAKS
The Hair-streaks are small butterflies with the eyes notched to allow
for the insertion of the bases of the antennae. The name is given on
account of the fine, hair-like markings which extend across the under
surface of the hind wings. In many species there is a tailed
projection or two on the hind inner margin of the hind wing. The
caterpillars are remarkable for the small head, so connected with the
body that it can be pushed forward in a characteristic way.
The Hair-streaks are among the most exquisite and delicate of all our
butterflies. A large proportion of them have the upper surface of the
wings toned in beautiful hues of grayish brown and the under surface
lighter gray, marked with dots and stripes, some of which are
brilliant in coloring. A few of the larger species are brilliantly
iridescent in purples, blues, and greens, marked with black. The males
have well-developed scent-pockets in many species, these being
commonly along the front border of the front wing.
A very interesting suggestion in regard to the possible function of
the curious tail projections was made nearly a hundred years ago by
some English entomologists and has since been discussed at
considerable length in various publications. It is that the slender
tails, together with the enlargement of the wing just back of them,
give the impression of a false head. Along with this unusual
development of the wing is to be considered the fact that these
butterflies nearly always alight head downward so that the false head,
furnished with what seem to be waving antennae, takes the place that
would naturally be occupied by the true head. Instances have been
reported in which this false head has apparently been nipped off by a
lizard and much evidence has accumulated to indicate that this curious
device may be a real protection in many cases. Of course, the loss of
the tails and the part of the wings adjacent would be comparatively
insignificant. In most cases, these projections on the wings are held
at right angles to the plane of the wing.
While nearly half a hundred species of Hair-streaks have been found in
North America, only a few of these are sufficiently abundant to
require discussion in this little book.
=The Great Purple Hair-streak=
_Atlides halesus_
It seems something of a reflection on the activities of American
entomologists to say that, after the lapse of more than a century
since Abbott studied the insects of Georgia, our knowledge of the
early stages of two of the largest Hair-streak butterflies is still
confined to the observations he made. Yet this is true, and one of
them--the Great Purple Hair-streak--is the largest species of the
group that occurs in the eastern United States. The other is the
White-M Hair-streak.
The Great Purple Hair-streak is a beautiful, iridescent blue creature,
as seen from above, with blackish borders around the blue. As seen
from below, the wings are dark brown, with red spots near the body.
The two tail-like projections are quite long. It is very large for the
group to which it belongs, measuring nearly two inches across the
expanded wings. It is a tropical form, extending into our southern
borders from California to Florida and occasionally occurring north as
far as southern Illinois. The larvae feed on oak. (_See plate, page
256._)
=The White-M Hair-streak=
_Eupsyche M-album_
The White-M Hair-streak is about two thirds the size of the Great
Purple species with less blue and more black on the upper wing
surface. The hind tail is slender and well developed, and the angle of
the wing just back of it is rounded out in an unusual fashion. The
lower surface of the wing is of a general grayish brown color, marked
by a white stripe, which takes the form of the letter M: hence its
name. This is also a southern species occurring at times as far north
as Ohio and even Atlantic City, New Jersey. The caterpillars feed upon
the leaves of oak and Astragalus or milk vetch.
There is also a third species of this group of whose history we are
ignorant except for Abbot's observations. It is an exquisite little
butterfly called the Least Purple Hair-streak (_Calycopis cecrops_)
and is apparently a tropical form which has spread into our Southern
states. It is especially beautiful because of the brilliant red and
white lines running across the under surface of both wings. It occurs
as far north as West Virginia and Kentucky and ranges westward at
least to the Mississippi Valley.
=The Gray Hair-streak=
_Uranotes melinus_
This exquisite little creature is capable of surviving under a great
variety of climatic conditions. It ranges from New Hampshire to
Florida and Central America, but apparently occurs only rarely north
of the United States. Perhaps the most distinctive feature in the
female is the orange spot just in front of a pair of tiny tails on
each hind wing, the rear one being curiously curved and about three
times as long as the other. In the male the shorter tail is absent.
The general color of the upper surface is a dark bluish gray, relieved
on the margin of each hind wing by a few white dots and the orange
spot already mentioned. The under surface is much lighter gray,
distinctly marked with two dark brown lines near the margin, the outer
line little more than a row of spots and the inner line with a white
edge. (_See plate, page 257._)
These small butterflies lay tiny though beautiful eggs upon a variety
of plants. The eggs hatch into curious little caterpillars that have
the appearance of slugs with small heads which can be extended as if
the little creature had really a rubber neck. The object of this
extensile head is seen when one finds the larvae feeding upon the
fruits or the seed-pods of its various food plants--hawthorn, hop,
hound's-tongue, and St. John's-wort. The caterpillar is able to thrust
its jaws into the interior of the seed-pods and devour their
contents. There seem to be generally two broods in a season, even in
the more northern parts of its range, while toward the south there are
probably at least three broods. The butterflies are found upon the
wing almost any time in summer, especially from early June until late
in August.
=The Banded Hair-streak=
_Thecla calanus_
This is one of the most familiar of the delicate little butterflies
grouped in the genus _Thecla_. It occurs rather commonly in a great
stretch of territory extending from Maine, west to Nebraska, south to
New Mexico and Texas, and east to Alabama and Georgia. It also occurs
in a limited area on the coast of California. The general color of the
upper surface is a dark brown, which in the male is marked near the
front edge of the fore wings with a distinct gray patch of scent
scales. The under side is similar in color to the upper except that
the outer half of the wing is marked by two series of broken lines in
white, blue, and brown and a brilliant bit of coloring just in front
of the tail projection of the hind wings; this coloring shows
beautiful tones of red, blue, and black.
These little butterflies may often be seen visiting the midsummer
flowers but are fully as likely to be found along the sides of a shady
road, where they rest upon the leaves of trees, shrubs, and herbaceous
plants. When disturbed, they fly up in small companies but soon settle
back again into their previous positions. They are lovers of sunshine
and may often be seen upon a leaf, with fully expanded wings, taking
a sun-bath. There is but one brood a year, butterflies appearing early
in summer and remaining for several weeks. They lay their tiny pale
green eggs upon the leaves of various trees, especially oaks and
hickories, and probably hawthorns. It is not known whether these eggs
remain unhatched as a rule until the following spring, or whether they
soon hatch and the young caterpillars hibernate without feeding. It is
probable that both conditions occur. In spring the larvae eat holes in
the leaves of their food plant and grow rather slowly, gradually
becoming brown or green slug-like caterpillars about half an inch
long. They finally change into greenish brown chrysalids from which
the butterflies emerge in early summer.
=The Striped Hair-streak=
_Thecla liparops_
In the Eastern states the distribution of this species is almost the
same as that of the Banded Hair-streak, but in the Central West the
outline of its region moves northward extending into Canada, above
North Dakota, and into Montana and Wyoming. It does not go so far
south, however, extending practically only to the southern borders of
Kansas and Missouri. The butterfly bears a striking general
resemblance to the other species just named, differing chiefly in the
fact that the under surface of the wings is much more thickly marked
with broken lines that extend nearer to the body. As a rule, it is not
common and consequently it is prized by collectors. Some good
observers have noticed that it is more likely to be found only on
flowers, instead of sunning itself on leaves. It is single-brooded,
hibernating either in the egg state or in that of the young larvae.
The food plants are varied, there being good evidence that the
caterpillar feeds upon all of these: apple, plum, shadbush, blueberry,
holly, chestnut, willow, thorn, and several kinds of oaks. Mr. W. F.
Fiske found a chrysalis of this species in the deserted nest of a tent
caterpillar in New Hampshire in early June, the butterfly emerging
later in the month.
=The Acadian Hair-streak=
_Thecla acadica_
This is one of the numerous butterflies that offers some young student
an opportunity to make real contributions to science. It is a
beautiful little creature, expanding scarcely an inch across its
outstretched wings, found from New England west to Montana along a
rather restricted area, which coincides pretty closely with the
southern part of the Transition Zone. There is a form on the Pacific
Coast which is commonly considered to be this same species.
These butterflies appear during July and August. They visit various
flowers but are especially likely to be found near willow thickets
along the borders of brooks and swamps. It is supposed that the eggs
are laid upon the willows and that they remain unhatched until the
following spring. Then they develop into little caterpillars that feed
upon the willow leaves and mature in time to form chrysalids early in
June. These chrysalids in turn disclose the butterfly early in July.
So far as I know the eggs themselves and the situation in which they
are laid have never been described.
=The Olive Hair-streak=
_Mitoura damon_
Very few butterflies have the distinction of showing a clear case of
protective resemblance to one kind of plant in both the adult and the
larval stages. This is the case, however, with this Olive Hair-streak
which is so intimately associated with our common red cedar, that
where one is found the other is likely to occur, although both
caterpillars and butterflies are seldom seen because they resemble the
twigs of the cedar so closely.
Along the Atlantic Coast this little butterfly occurs from New
Hampshire to Florida, and westward to a line drawn from Dakota to
Texas. The upper surface of the wings is rather dark olive-brown and
the under surface, so far as it is exposed when the butterfly is
resting, is of a greenish hue that harmonizes with the green of the
red cedar twigs. There are also, on the under surface, some irregular
lines and dots of red, brown, and white which probably help in
rendering the insect inconspicuous when it is resting among a cluster
of twigs.
The yearly history of this beautiful little butterfly differs from
that of most of its relatives. The species winters in the chrysalis
state, the first brood of butterflies bursting forth early in May.
These lay their eggs upon or between the scales of the red cedar
twigs, especially those which bear flowers. About a week later the
eggs hatch into tiny caterpillars that feed upon the scale-like
leaves, continuing to eat and grow for nearly six weeks before they
reach their full size. These caterpillars are so similar in color that
they are difficult to see, and they have a remarkable protective
device in that the first ring behind the head is developed into a
shield which covers the head, hiding it so completely that the
movement of the jaws in feeding is effectively concealed. Late in June
they change to chrysalids, part of which appear to remain in this
condition until the following spring, while most of them give forth a
second brood of butterflies in July. These butterflies lay eggs for a
second brood of larvae that mature into chrysalids during September,
and hibernate in this condition until the following spring.
Consequently, in the Northern states, the collector should look for
fresh specimens in May and early June and again in July and early
August.
These butterflies visit various flowers, apparently preferring rather
small blossoms, such as those of the Mouse-ear Everlasting, which is
in bloom when the first brood is flying, and the various members of
the mint family, especially spearmint, as well as the sumacs, which
are in bloom when the second brood is on the wing. The time between
flower visits seems to be spent at rest upon the red cedar branches,
and one of the surest ways to find the butterflies is to give these
trees a sudden jar, which starts them into flight. In fact, they may
often be seen flying around the tops of the cedars a score of feet
from the ground.
_Synopsis of the Hair-streaks_
_Great Purple Hair-streak_ (_Atlides halesus_ or _Thecla halesus_).
Wing expanse 1 3/4 inches. Upper wing surface bright blue with
blackish margins, the blackish coloring extending nearly to the middle
in the female. Two distinct tails on each hind wing. Under surface
sepia brown with blue and red spots. Abdomen orange below.
_White-M Hair-streak_ (_Eupsyche m-album_ or _Thecla m-album_). Wing
expanse 1 1/3 inches. Upper wing surface blue with wide blackish
margins in both sexes. Under surface marked with whitish lines
suggesting the letter M, with a reddish spot near it. Each hind wing
with two small tails.
_Least Purple Hair-streak_ (_Calycopis cecrops_ or _Thecla cecrops_).
Wing expanse 1 inch or less. Upper wing surface dark brown, more or
less marked with blue, especially at base of front wings and inner
half of hind wings. Under wing surface marked with a brilliant red
line edged outside with white. Two very fine tails on hind wings with
brightly colored spots near their base on lower surface.
_Gray Hair-streak_ (_Uranotes melinus_ or _Thecla melinus_). Wing
expanse 1 1/5 inches. Upper wing surface bluish gray with a brilliant
red spot at base of tails on hind wing. Lower wing surface much
lighter gray, each wing marked with a brown and white stripe and a row
of dots nearer the margin.
_Banded Hair-streak_ (_Thecla calanus_). Wing expanse 1 1/5 inches.
Upper wing surface dull dark brown, commonly without markings although
sometimes there is an orange spot on each hind wing. Lower wing
surface a little lighter than upper with bright red and blue spots at
the base of the tiny tails, and with distinct narrow blue and white
broken bands extending across the outer half of each wing.
_Striped Hair-streak_ (_Thecla liparops_). Wing expanse 1 inch. Very
similar to the Banded Hair-streak, but having more white markings on
the lower surface of the wings.
_Acadian Hair-streak_ (_Thecla acadica_). Wing expanse 1 1/3 inches.
Upper wing surface blackish brown with a slaty tinge, and red spots at
base of the single short tail on each hind wing. Lower surface bluish
gray with many small blackish spots edged with white arranged in two
principal rows on the outer half of each wing. Larger orange-red spots
on each side of base of the tail on each hind wing.
_Olive Hair-streak_ (_Mitoura damon_ or _Thecla damon_). Wing expanse
1 inch or less. Upper wing surface olive-brown, more yellow in the
male than the female. Tips of tiny tails on hind wing whitish. Lower
surface green except where upper wing is covered by lower: this part
is brown. The green is marked with a row of white spots on each front
wing and two distinct rows of brown and white spots on each hind wing,
with black spots between.
THE TRIBE OF THE COPPERS
The members of this tribe are well characterized by their name, for
most of them show on the upper wing surface tones of coppery brown,
more or less marked around the margin with darker shades. On the under
side of the tarsi there are numerous spines in irregular clusters. In
the chrysalis there are curious hair-like projections on the skin,
which are short and shaped like tiny toadstools or mushrooms.
While some of the Coppers are very abundant, the majority are rather
rare. Only a few species are sufficiently widely distributed to
require description here.
=The Wanderer=
_Feniseca tarquinius_
In many orders of insects there are whole families whose larvae are
habitually carnivorous, feeding entirely upon other kinds of insects.
This is especially so in case of the beetles, the flies, the true
bugs, and the great order to which the bees and wasps belong. Among
the scale-winged insects, however, carnivorous caterpillars are rare,
seldom occurring among the moths and in hardly more than one species
among the butterflies. This one exception is the modest-looking little
butterfly fancifully called the Wanderer, perhaps because instead of
frequenting the flowery fields where other butterflies congregate it
wanders in and out among the alders by brooks and ponds, alighting
oftener upon a leaf or twig than upon a flower--the latter apparently
lacking for it the attraction it has for other butterflies.
If you watch one of these copper-hued creatures for awhile, however,
you will soon see that its wandering is not aimless but has rather a
method all its own. Perhaps you will see it alight upon an alder twig
on or above which you are likely to notice curious woolly white
excrescences. If you are close enough you will probably see the
butterfly uncoil its tongue and sip up a liquid on twig or leaf--the
exudations of the woolly aphids that make up the supposed excrescence
and suck the sap from the bark. Much of this sap passes through the
bodies of the aphids and collects in liquid globules on twigs and
leaves, forming a sort of honey-dew which is much sought after by
flies, wasps, and other insects. It seems to form the chief sustenance
of these Wanderers.
But many of these butterflies have another purpose besides that of
sipping the honey-dew. Should you watch one of the mother butterflies
carefully you would be likely to see her alight on or near a colony of
woolly aphids and run rather rapidly over them in a wasp-like manner,
finally stopping long enough to lay a tiny, roundish, slightly
flattened egg upon the twig, generally on the under side, and only one
in a place. Then she may continue her way, wandering lazily along the
alder-bordered stream.
Let us now centre our interest upon the egg. Three or four days later
it hatches into a curious caterpillar. Instead of having mouth parts
fitted for biting leaves as is the case with most butterfly larvae, it
has one fitted for grasping, piercing, and sucking the juices of the
plump bodies of the aphids, which it finds hard by its place of birth.
It also has silk spinnerets connected with its mouth, so it is able to
spin a web to shelter it from being run over by its intended victims.
The newly hatched larva is not slow to take advantage of the
facilities with which it is provided. It at once begins to spin a web
above and around itself, from the end of which it reaches out for the
nearest aphids, sucking their life-blood and casting their empty skins
to the discard of its protecting web. The skins thus serve as an
additional shelter so that, as the caterpillar moves forward,
increasing the number of its victims from day to day, it extends its
web and the protection of the cast skins intermingled with it, while
through all--the cast skins, the silken web, and even the hairs on the
body of the caterpillar--there runs a woof of the woolly
excretion--effectually concealing the larva from sight.
The woolly aphids thus serve as the sole food of the caterpillar
during its brief life as a larva. Perhaps because of the pre-digested
nature of its food, it is able to mature much sooner than most
butterfly larvae. In about eleven days after hatching it is ready to
change to a chrysalis, having undergone during this period only three
moults, instead of at least four as with other caterpillars. Each
caterpillar then changes to a chrysalis which is remarkable because
the form and color of its back bears a striking resemblance to the
face of a miniature monkey. It remains in this condition nearly a
fortnight and then emerges as a butterfly.
In New England and the Northern states the short life of the larva
enables this insect to mature three broods each season. Farther south
there are probably more, for this species is widely distributed in
eastern North America, occurring from Nova Scotia to Georgia and west
to the Mississippi Valley.
=The American Copper=
_Heodes hypophlaeas_
This little butterfly is one of the most generally abundant insects in
the northern part of North America. It commonly occurs from ocean to
ocean, from the Hudson Bay region to the latitude of Georgia, and it
flies freely in city parks and village yards as well as in the more
open spaces of field and forest. When seen through a lens it is very
beautifully colored, the coppery red of the wings being overspread
with conspicuous black dots and a touch of orange around the outer
border. The expanded wings measure just about an inch, so that this is
one of the smallest of our common butterflies.
The caterpillars of the American Copper feed upon sorrel, one of the
commonest weedy plants of waste places everywhere. The rusty red
blossoms of the sorrel harmonize in color with the color of the
butterfly, which is frequently to be seen flying slowly above the
plants, stopping now and then to lay its eggs singly upon the leaves
or stems. Each egg soon hatches into a curious caterpillar, which
looks more like a slug than the usual type of butterfly larva. It
feeds upon the succulent tissue of the sorrel leaf, at first biting
small holes in the under surface. As it gets larger it feeds more
freely and is likely to make channels instead of holes. It matures in
about three weeks, changing into a chrysalis under the shelter of a
stone or board. A little later it again changes to a butterfly.
There is an interesting variation in the number of broods of this
butterfly each season. In regions where it has been studied it has
been found to be double-brooded in northern New England and
triple-brooded in southern New England and the Atlantic states. It is
probable that in its far northern home in the Hudson Bay territory it
is only single-brooded. It is thought that the insect hibernates as a
chrysalis.
These little butterflies are so small and fly so near the ground that
they are likely to be overlooked by the casual observer. They
frequently alight to sun themselves or to sip nectar from many kinds
of flowers. They begin their day's work early in the morning and
continue well into the evening. Then they find a roosting-place, head
downward upon a blade of grass, where they sleep until wakened by the
morning sunshine.
[Illustration: _From a drawing by W. I. Beecroft_
FIVE INTERESTING BUTTERFLIES
The Spring Azure (_p. 258_) at the top; the Falcate Orange-Tip
(_p. 94_) next; the Bronze Copper (_p. 257_), female, next;
the Spring Azure (_p. 258_) resting on a leaf, next; and the
Great Purple Hair-streak (_p. 243_), female, below.]
[Illustration: _See page 245_
STAGES OF THE GRAY HAIR-STREAK]
=The Bronze Copper=
_Chrysophanus thoe_
This butterfly is nearly twice as large as the American Copper to
which the female of the present species bears a striking resemblance.
The Bronze Copper is a rare species, occurring from New England nearly
to the Rocky Mountains. The slug-shaped yellowish green caterpillar
feeds upon dock and related plants. (_See plate, page 256._)
_Synopsis of the Coppers_
_The Wanderer_ (_Feniseca tarquinius_). Wing expanse 1 1/4 inches.
Upper wing surface tawny brown, each wing more or less marked with
dark brown spots, the distinction between the colors being clear-cut,
and the lines between having an angular effect. Lower surface of front
wings similar in colors to upper with dark spots rectangular. Under
surface of hind wings mottled with irregular spots of pale brown.
_American Copper_ (_Heodes hypophlaeas_ or _Chrysophanus
hypophlaeas_). Wing expanse 1 inch. Upper surface of front wings tawny
orange with margins and rectangular spots blackish. Upper surface of
hind wings coppery red with a tawny orange band on outer margin. Lower
surface of front wings much like upper surface; that of hind wings
grayish marked with dark spots and an orange line near the margin.
_Bronze Copper_ (_Chrysophanus thoe_). Wing expanse 1 1/2 inches.
_Male._ Upper wing surface coppery brown marked with dark spots and a
tawny orange sub-marginal band along outer margin of hind wings. Under
surface of front wings lighter orange with blackish spots and of hind
wings grayish with blackish spots and an orange sub-marginal band.
_Female._ Upper surface of front wings tawny orange with blackish
spots.
THE TRIBE OF THE BLUES
These beautiful little butterflies are well named, for the majority of
them are colored in exquisite tints of blue. They are distinguished
from the Coppers by this blue coloring, as well as by the fact that
the spines on the under side of the tarsi are arranged in rows rather
than in clusters and are comparatively few in number. The body is
rather slender and the under surfaces of the wings are generally
dotted in a characteristic fashion. Most of the two score or more
species found in North America occur on the Pacific Coast or in the
Southwest, less than half a dozen being common in the eastern region.
=The Spring Azure=
_Cyaniris ladon_
For a wee bit of a gossamer-winged creature that expands scarcely an
inch across its outstretched wings, the Spring Azure has caused
American scientists an immense amount of patient labor. Over the vast
territory from Labrador across to Alaska and south to the Gulf of
Mexico, this little blue butterfly exists in so many different forms
that it requires special analytical keys to separate them. Not only
does it vary geographically so that in one locality we find one form
and in another a different form, but it also varies seasonally to a
marked degree. As one would expect there is a striking difference in
its annual cycle between Labrador and the Gulf Coast. In the far
northern region there is but one brood a year, while in the southern
region there are at least two and perhaps more.
The variations in this butterfly are shown by the differences in the
marking of both surfaces of the wings. These markings may run from a
faint blackish border along the extreme margin and a few faint dots
upon the under surface, to a wide black margin around the wings and a
deep abundant spotting of the under surface. The markings of the
various forms are so uniform that the varieties are easily
distinguished. It is beyond the scope of this book to attempt to
differentiate all these varieties but any reader interested will find
an admirable summary of the conditions illustrated by an excellent
plate in Comstock's "How to Know the Butterflies." The species as a
whole may be known from the fact that the upper surface is blue, the
lower surface ash-gray, more or less spotted with dark brown, and the
wings are without tails. (_See plate, page 256._)
_The Strange Structures of the Larvae_
A remarkable variation of the adults is sufficient to give this
species a special interest, but the larvae also have a unique
attraction for the naturalist. The mother butterflies lay their eggs
upon the flower buds of various plants, especially those which have
clustered racemes of blossoms. These eggs hatch into minute slug-like
larvae which feed upon the buds, commonly burrowing through the calyx
lobes and devouring the undeveloped stamens and pistils inside. They
finally change to chrysalids, which are more or less securely attached
to a central flower stalk, from which in due time the butterflies
emerge. So far there is nothing remarkable about this story of the
life of the Spring Azure, but that is yet to come.
These little caterpillars are subject to attack by tiny parasitic
flies which lay eggs in their bodies. Each egg hatches into a still
more tiny maggot that lives at the expense of the tissues of the
caterpillar and finally kills it. When one of these little
caterpillars has its head buried in the round ball of a flower bud,
about half of its body is exposed defenseless, so that the little fly
that lights upon it to lay her egg cannot even be dislodged by the
head of the caterpillar, as is often the case with other species.
There is a very curious provision for defense, however. If you look
carefully through a lens at the hind part of the body you will find a
little opening on the back of the seventh abdominal ring. This opening
leads to a sort of tiny pocket, a pocket which the caterpillar can
turn inside out when it so desires. Now the curious thing about it is
that the caterpillar, while this pocket is concealed in its body, is
able to secrete in it a drop of liquid which we presume to be sweet to
the taste. When the little pocket is partly filled with this drop of
liquid the caterpillar turns it inside out in such a way that the
liquid drop remains in position on top of the protruded pocket.
Perhaps you ask what is the good of all this complicated arrangement?
If you could see what happens when the little drop of what--for lack
of a better name--we shall call honey-dew is exposed, you would begin
to guess the reason. Wherever these larvae are found you will also
find many ants wandering round among them, and the moment the
honey-dew appears these ants begin to sip it up. When it is all gone
the little caterpillar draws in its pocket again and presumably begins
to store up another bit of liquid. It is certainly a curious example
of what the naturalists call symbiosis, which simply means a living
together of two animals, each helping the other in some way. In this
case it is easy enough to see how the caterpillar helps the ant, but
perhaps you are wondering in what possible way the ant may help the
caterpillar. I hardly dare give the most plausible explanation for
fear some one will cry out, "Nature-faker!" But fortunately the
explanation is based upon at least one precise observation by W. H.
Edwards, one of the most careful and reliable naturalists America has
produced, who lived before the recent era of Nature-fakers and was
never accused of sensationalism. Mr. Edwards saw an ant drive away
from one of these caterpillars a little parasitic fly which apparently
was searching for a victim. Consequently, it would appear that the
ants helped the caterpillars by protecting them from these arch
enemies.
This is by no means an isolated example of the relations between ants
and other insects. It has been known for hundreds of years that the
ants use the aphids as a sort of domestic milk-producer, attending the
aphids at all times and even caring for their eggs throughout the
winter season. As the plant-lice live in colonies, sucking the sap of
their host plant, they are attended by great numbers of ants that
feed upon the honey-dew which passes through their bodies. In many
cases the ants have been observed to stroke the aphids with their
antennae in a way which seems to induce the aphid to give out a drop
of the sweet liquid for the ant to lap up. In a similar way these ants
seem sometimes to stroke these little caterpillars with their antennae
and thus to induce them to turn their little pockets inside out with
the drop of liquid at the tip. This is certainly an unusual and most
interesting relation between two insects far separated by their
structural characters.
The little pocket that I have thus described is situated upon the
seventh segment of the abdomen. Just back of it there are two other
openings which are even more curious in their structure. These are
provided with some slender tentacles on which there are circles of
hairy spurs. These structures are a great puzzle to naturalists. It is
difficult to explain what they are for unless we assume that they
relate in some way to the honey-dew pocket on the seventh ring. The
only plausible explanation is that these serve to advertise to the
ants, by giving off a distinctive odor, that there is nectar near at
hand to be had for the asking. They would thus be analogous in a way
to the fragrant scent of flowers which is for the purpose of
advertising to the bee the fact that nectar or pollen or both are near
at hand and may be had for the asking. In the case of these
caterpillars, however, if this is the true explanation it is a most
wonderful provision and one which would be likely to tax the ingenuity
of man's mind for a long while before it was originated.
So this little butterfly which greets us in every spring, like "a
violet afloat," to quote Mr. Scudder's happy phrase, is full of
interest at all stages of its existence. It should lead one to a new
respect for the familiar things in the natural world when one learns
how baffling to the wits of the wisest scientist is this little
creature with its protean forms and the wonderful structure of its
caterpillars.
=Scudder's Blue=
_Rusticus scudderi_
This beautiful little butterfly is perhaps the most richly colored of
all our northern Blues. The upper surface of the wings in the male is
a nearly uniform hue, except for a narrow dark border around the
margin. In the female there is, in addition, a series of black-centred
orange spots inside of the black border, the series being more
prominent on the hind wings than on the front ones. The under surface
is very pale with distinct marks in black scattered over the basal two
thirds, with a row of orange spots outside of these and another row of
small blackish spots just inside of the blackish border stripe.
This butterfly is a northern species. It occurs in New England, New
York, and Michigan, and thence extends far north into Canada. The
caterpillar feeds upon blue lupine and apparently the butterfly is
likely to be found in most places where this plant grows. The eggs are
laid upon the leaves or stems and the little caterpillars come out of
the shells through small holes which they have gnawed.
"The caterpillar," wrote Mr. Scudder, "has a very extensible head and
flexible neck, and its manner of feeding immediately after birth is
rather remarkable; it pierces the lower cuticle of the leaf, making a
hole just large enough to introduce its minute head, and then devours
all the interior of the leaf as far as it can reach--many times the
diameter of the hole--so that when the caterpillar goes elsewhere, the
leaf looks as if marked with a circular blister, having a central
nucleus; the nearly colorless membranes of the leaf being all that is
left, and at the central entrance to the blister the upper membrane
only." Later in its life it often modifies this feeding habit
somewhat, and as it approaches full growth it is likely to devour the
entire blade of the leaf.
These larvae have the curious nectar-secreting glands on the seventh
abdominal segment which are discussed in connection with the preceding
species. Many ants are attracted by this secretion so that it often
happens that the easiest way to find the caterpillars is to look for
these attendants. In New England there are two broods of the
butterfly, one appearing early in June and the other late in July.
=The Tailed Blue=
_Everes comyntas_
The tiny, threadlike, white-tipped tail projecting from the hind angle
of the hind wings distinguishes this species at sight from any other
found in eastern North America. The species, however, occurs clear to
the Pacific Coast and ranges north and south over most of the northern
continent. The small slug-like caterpillar feeds upon the flowers of
various clovers and other legumes.
=The Silvery Blue=
_Nomiades lygdamus_
It would be a distinct privilege to work out the life-history of this
exquisite little butterfly. Although the adult was described as long
ago as 1842, the early stages seem to be still unknown. The species
occurs in the South Atlantic states, extending west as far as
Wisconsin.
_Synopsis of the Blues_
_Tailed Blue_ (_Everes comyntas_ or _Lycaena comyntas_). Wing expanse
1 inch or less. A slender tail projecting from each hind wing. Upper
wing surface of varying tones of blue, the males lighter than the
females. Lower wing surface grayish white with scattered spots.
_Scudder's Blue_ (_Rusticus scudderi_ or _Lycaena scudderi_). Wing
expanse 1 inch or less. No tails on hind wings. Eyes without hairs.
Upper wing surface blue; female has dusky margins on front wings and
an orange border with blackish spots near outer margin of the hind
wings. Lower wing surface bluish gray with many small spots.
_Silvery Blue_ (_Nomiades lygdamus_ or _Lycaena lygdamus_). Wing
expanse 1 inch. No tails on hind wings. Eyes hairy. Upper wing surface
silvery blue with dusky margins which are broader in the female. Lower
wing surface ashy gray with many darker spots.
_Spring Azure_ (_Cyaniris ladon_ or _Lycaena ladon_). Wing expanse 1
inch. No tails on hind wings. Eyes hairy. Upper wing surface azure
blue with black border markings varying greatly, more pronounced in
the female. Lower wing surface slaty brown with many darker spots.
PART III
THE SKIPPER BUTTERFLIES
SUPERFAMILY _Hesperioidea_
The true butterflies are so distinct in their structure and many
of their habits from the Skippers that the most careful students
of the order are pretty well agreed in making the two great
superfamilies--Papilionoidea, the true butterflies, and Hesperioidea,
the Skipper butterflies. The latter includes these two families:
The Giant Skippers (_Megathymidae_).
The Common Skippers (_Hesperiidae_).
These insects as a whole are distinguished from the higher butterflies
by their large moth-like bodies, small wings, hooked antennae (except
in the Giant Skippers), by having five branches of the radius vein
arising from the large central cell. The larvae spin slight cocoons in
which to pupate and the pupae are rounded rather than angular.
The two families are readily distinguished by the differences in their
size and the structure of the antennae. The Giant Skippers measure two
inches or more across the expanded wings and have comparatively small
heads, with the clubs of the antennae not pointed or recurved. The
Common Skippers are smaller, and have very large heads with the
antennal clubs drawn out and recurved.
THE GIANT SKIPPERS
FAMILY _Megathymidae_
Although large in size, the Giant Skippers are few in numbers. Only
one genus and five species are listed for North America, and
practically all of these are confined to the Southwestern states and
Mexico. Some of them extend as far north as Colorado and as far east
as Florida.
[Illustration: Megathymus yuccae. Female. (After Riley.)]
So far as the story of its life is concerned, the best-known species
is the Yucca-borer Skipper (_Megathymus yuccae_) which was carefully
studied by the late Dr. C. V. Riley. As will be seen from the picture
above which represents the adult, natural size, this skipper has a
body so large as to suggest some of the heavy-bodied moths. The wings
are dark brown, marked with red-brown spots and bands. They fly by day
and when at rest hold the wings erect.
These adults lay eggs upon the leaves of Spanish needle or yucca. The
eggs soon hatch into little caterpillars which at first roll parts of
the leaves into cylinders, fastening the sides in place by silken
threads, and later burrow into the stem and root, often making a
tunnel a foot or more deep. Here the caterpillars remain until full
grown. They are then nearly four inches long and half an inch in
diameter. They now pupate in the top of their tunnel and in due season
emerge as adults.
THE COMMON SKIPPERS
FAMILY _Hesperiidae_
The Skippers are the least developed of the butterflies. They show
their close relationship to the moths both by their structure and
their habits. The larvae make slight cocoons before changing to
chrysalids, and these chrysalids are so rounded that they suggest the
pupae of moths rather than those of butterflies. The common
name--Skippers--is due to the habit of the butterflies--a jerky,
skipping flight as they wing their erratic way from flower to flower.
In North America the Skipper family includes nearly two hundred
species grouped in about forty genera. From this point of view it is
the largest family of our butterflies, but on account of the small
size and limited range of most of the species it has by no means the
general importance of such families as the Nymphs, the Swallowtails,
or the Pierids.
The Skippers are remarkable for the uniformity of structure in each
stage of existence. The butterflies have small wings and large bodies.
The broad head bears large eyes without hairs, but with a tuft of
curving bristles overhanging each. The antennae are hooked at the end
and widely separated at the base. Each short palpus has a large middle
joint and a small joint at the tip. The fore wings project out at the
front angle and the hind wings are folded along the inner margin.
There are six well-developed legs in both sexes. The colors are
chiefly various tones of brown, dull rather than bright, and many of
the forms resemble one another so closely that it is difficult to
separate them.
The Skipper caterpillars have stout bodies and are easily known by the
constricted neck. Most of these have the habit of making nests from
the leaves of the food plants, weaving them together with silken
threads. In a similar way each also makes a slight cocoon when it is
ready to change to a chrysalis.
The Skippers found in eastern North America are commonly grouped into
two types--the Larger Skippers and the Smaller Skippers. The
characteristics are given in the paragraph immediately following and
the one on page 278.
THE TRIBE OF THE LARGER SKIPPERS
The butterflies of this tribe have that part of the club of the
antenna, which is recurved, about as long as the thicker part below
it. As a rule, the abdomen is distinctly shorter than the hind wings.
The caterpillars are rather short and thick, and the upper part of the
head, when looked at from in front, is square or roundish rather than
tapering. The chrysalids have the tongue case attached throughout its
length and stopping short of the tips of the wing cases.
=The Silver-spotted Skipper=
_Epargyreus tityrus_
One can seldom draw hard and fast artificial lines in nature. There
are all sorts of intermediate conditions which disturb arbitrary
classifications. It might seem simple enough to say that some insects
are leaf-rollers and others are tent-makers, but as a matter of fact
in the case of the Silver-spotted Skipper we have an insect which
starts its larval life as a leaf-roller and finishes it as a
tent-maker. Its life-history is rather interesting and easily
observed, if one can find the larvae at work upon the leaves of
locusts and other trees. (_See plates, pages 272-273._)
The Silver-spotted Skipper is one of the largest butterflies of the
interesting group to which it belongs. It lays its eggs upon the upper
surface of the leaflets of locusts and other plants of the legume
family. In less than a week each egg hatches into a little caterpillar
with a very large head and a comparatively large body, tapering
rapidly toward the hind end. This little creature cuts out from one
side of the leaf a small round flap which it turns over and binds in
place by silken threads to make a home for itself. This little home
shows considerable variation in its construction but it usually has an
arched dome held in place by strands of silk running from the eaten
fragment to the surface of the leaf. It remains an occupant of this
home until after the second moult. About this time it becomes too
large for its house and deserts it to make a new one generally by
fastening together two adjacent leaves. These are attached along the
edges by silken strands in such a way as to give considerable room.
It leaves one end open as a door out of which the caterpillar crawls
to feed at night upon near-by leaves, returning to the house for
shelter during the day. They continue to use this habitation until
they are full grown as caterpillars and sometimes they change to
chrysalids within it. More commonly, however, they crawl away both
from the leafy case and the tree that bears it and find such shelter
as they can upon the ground near by. Here they spin slight silken
cocoons within which they change to chrysalids. In the more Northern
states there is but one brood a year, so these chrysalids remain in
position until early the following summer when they come forth as
butterflies. Farther south there are two broods each summer, the
second brood of butterflies appearing chiefly in August.
The Silver-spotted Skipper derives its name from the distinct silvery
spots upon the under-wing surface against a background of dark brown.
The butterflies appear in the Northern states early in June and remain
upon the wing for several weeks, being found even in August. They fly
very rapidly and are difficult to catch in an insect net except when
they are visiting flowers.
This species is widely distributed, occurring from ocean to ocean over
nearly the whole of the United States. It extends into Canada only in
the eastern part and is not found in the Northwestern states.
=The Long-tailed Skipper=
_Eudamus proteus_
This is perhaps the most easily recognized of all the Skippers found
in the United States for it is the only one that looks like a
Swallowtail. Its hind wings project backward as long, broad tails in a
way that marks the insect at once as different from anything else. It
expands nearly two inches and when the front wings are spread at right
angles, the distance from the apex of the front wing to the end of the
tail of the hind wing just about equals the expanse. The general color
is dark brown, with about eight more or less rectangular silvery spots
on each front wing.
This is distinctly a tropical species which is common along the Gulf
Coast from Mexico to Florida. It ranges north along the Atlantic Coast
to New York City and even to Connecticut. In the South Atlantic states
it is common, but toward the northern limits of its range it is very
rare.
In the West Indies this butterfly is very common and has been observed
to rest with its wings vertical, the front ones held far back between
the hind ones and the tails of the latter held at right angles to the
plane of the wings. Apparently, this curious fact was first noted by
Dr. G. B. Longstaff. Of course in museum specimens the wings have been
flattened into the same plane during the process of drying, so that
this peculiarity would not be noticed.
[Illustration: _Photograph by A. H. Verrill_ _See page 270_
Upper Surface
Lower Surface
THE SILVER-SPOTTED SKIPPER
(About twice natural size)]
[Illustration: _From a drawing by W. I. Beecroft_
_See page 270_
THE SILVER-SPOTTED SKIPPER
Caterpillar, chrysalis and adult]
=Juvenal's Dusky-wing=
_Thanaos juvenalis_
There are few trees which have so interesting a set of insects
attacking them as does the oak. It would be a simple matter to find
abundant material for a large volume by making a study of the
life-histories of the various insects that live upon or within the
various tissues of this tree. The leaves alone provide a home for a
remarkably large number of insect species scattered through a great
many orders and families. The thickened blades seem to furnish an
ideal opportunity for many larvae to get their living, and they are
particularly useful to those which need to make a winter nest.
By a little searching almost any time after the middle of June, one is
likely to find a curious caterpillar home upon some of the oak leaves.
The margin of the blade has been turned over, generally from above
downward but sometimes from below upward, and has been fastened down
to the main expanse of the blade by means of golden threads; commonly
this fastening is not continuous but is more or less intermittent, so
that the turned-over margin is likely to have an irregular border
where it joins the blade. Inside of this tubular construction a rather
unusual looking worm-like caterpillar is probably to be seen. Late in
the season it will probably be nearly an inch long, with a smooth
greenish body and a head that may be a bit brownish and more or less
marked on the sides with orange tones.
This is the larva of one of the most widely distributed
Skippers--Juvenal's Dusky-wing. The species is found from southern New
Hampshire west to the Great Plains and south to the Gulf of Mexico. In
most localities it is seldom abundant but yet is so general that it
may be found by almost every persistent collector. The wings expand
about an inch and a half and are of a dull brownish color, more or
less marked with darker and lighter spots. Toward the northern limits
of its range there is but one brood a year but farther south there are
two, although it is not improbable that some of the caterpillars of
the first brood remain unchanged throughout the season, so that the
insect is both single- and double-brooded in the same locality.
_The Yearly Cycle_
The yearly cycle in southern New Hampshire may be taken as an
illustration of the life of the species in regions where there is but
one brood. The butterflies appear in open woods and on cut-over lands
in May and June. They lay eggs upon the twigs of oak trees, one egg in
a place and generally near a leaf stem. The egg soon hatches into a
little caterpillar that crawls upon a near-by leaf and begins the
construction of its tubular nest by bending over the margin and sewing
it with golden silk. It utilizes this nest chiefly as a tent for
resting and sleeping and wanders away from it generally to another
leaf when it is ready to feed. It grows very slowly, having before it
all the weeks of summer to complete its caterpillar growth. As it gets
larger it needs a new tent and is likely to desert its early one. When
it does this some observers have noted a curious habit. It cuts loose
all the silk that binds the margin of the leaf down upon the blade so
that the flap is free to spring back to its original position. It
would be difficult to suggest an adequate explanation for this habit.
When autumn comes our caterpillar is faced with the problem of passing
through the winter successfully. It must shelter itself from birds,
spiders, predaceous beetles, and many other enemies. It must find a
means of keeping out of the reach of snow and rain, for while it can
survive a great degree of cold as long as it keeps dry, it might
easily be killed by freezing up with moisture. But the caterpillar is
able to provide against these dangers. It has apparently an abundant
supply of liquid silk to secrete from the silk glands in its head, so
it lines its tubular tent with a dense silken web that effectually
excludes enemies and moisture. It thus has on the outside of its nest
the thick oak leaf and on the inside a dense soft lining that makes a
most admirable winter protection. So it remains here throughout the
winter, the leaf commonly staying on the tree until early spring. Then
leaf, nest, and enclosed caterpillar are likely to drop to the ground
to remain until spring arrives in earnest. Just what happens then
seems to be a bit doubtful. The caterpillar changes to a chrysalis,
but whether it first works its way out of its winter nest and makes a
new and less dense covering seems not to be certainly known. Here is
another good opportunity for some careful observations.
At any rate, the caterpillar changes to a chrysalis, and late in
spring it changes again to an adult butterfly that flits about on
dusky wing for a few weeks before it dies.
=The Sleepy Dusky-wing=
_Thanaos brizo_
The appearance of this butterfly both as to size and marking is very
similar to that of Juvenal's Dusky-wing except that the white spots
are not present on the front wing of this species. The life-histories
of the two species as well as their distribution seem to be closely
parallel. The present butterflies are to be found early in summer in
the same oak barrens as the other, the blueberry blossoms being freely
visited for nectar by both species.
=Persius's Dusky-wing=
_Thanaos persius_
This is a rather small, dark brown Skipper, with a few white spots
toward the apex of the front wing, but otherwise not marked except for
a very pale transverse band which is almost obsolete. The butterfly is
found from ocean to ocean along the northern tier of states. It also
occurs in the Eastern states as far south as Florida as well as in the
states along the Pacific Coast.
The food plants of the caterpillars differ from most of those of the
other Skippers. The butterflies lay their yellowish green eggs, one in
a place, upon the leaves of willows and poplars. These soon hatch into
little caterpillars each of which cuts out a small flap along the
margin of the leaf and folds it over, fastening it in place with
silken threads. It thus forms a protecting nest within which it
remains during the day, going forth at night to a neighboring part of
the same leaf or to another leaf, and feeding upon the green surface
tissues. In this first caterpillar stage it does not eat the veins to
any extent. As it becomes larger it constructs a larger nest and feeds
more freely upon the leaf tissues. When about half grown it has the
curious habit of biting out small holes here and there in the blade so
that the leaf takes on a very unusual appearance. The presence of
these holes is generally the easiest way to find the caterpillars, for
when the holes are seen, a little searching is likely to show one the
characteristic tent-like nest.
After a few weeks the caterpillars become full grown. They then sew
themselves in for the winter, fastening all of the crevices in the
nest so securely with silken webbing that a very serviceable winter
cocoon is formed. An interesting fact is that this sewing up for the
winter is likely to take place about midsummer, the caterpillars
remaining quiet from this time until the following spring. The nests
of course fall in autumn with the leaves and the caterpillars remain
unchanged until April or May, when they transform into chrysalids to
emerge in May as butterflies. There appears to be normally but one
brood a year although there is some evidence of a partial second
brood.
=The Sooty Wing=
_Pholisora catullus_
This is one of the smallest of the blackish Skippers and may be known
by its small size, expanding less than an inch, and the series of five
white dots near the apex of the front wing, these dots being more
distinct on the under surface. The species is widely distributed,
occurring over practically the whole of the United States, except in
the states along the Canadian border from Wisconsin west--and in
several of these it is found along their southern limits.
This butterfly is of particular interest because it is one of the
comparatively few species that habitually occur in gardens and
cultivated fields. The reason for this is that the eggs are laid upon
white pigweed or lambs' quarter, the common garden pest of the genus
Chenopodium. The eggs are laid singly, generally on the upper surface,
and hatch in about five days into tiny caterpillars that make a little
shelter for themselves by cutting out the edge of a leaf and folding
over the blade, sewing it in place by a few silken threads. Here they
remain and feed upon the green pulp of the succulent leaves either
within the nest or near by outside. They remain in these cases until
the time for the first moult, when they are likely to line the inside
of the silken web before moulting. After this they make new cases for
concealment and shelter, the cases as they grow older being generally
made of two or more leaves securely bound together by silken web along
their margin. When they become full grown, they spin a silken cocoon
and change to yellowish green chrysalids from which the butterflies
emerge a little more than a week later.
This species is supposed to be double-brooded in the north. The
full-grown caterpillars of the second brood sew up their leafy cases
very carefully, making them of such thick silken webbing that they are
watertight. They remain in these coverings until the following spring,
when each changes, still within the case, into a chrysalis from which
the butterfly comes forth in April or May.
THE TRIBE OF THE SMALLER SKIPPERS
In the members of this tribe the tip beyond the club of the antenna is
short and the abdomen is long enough to extend as far as or farther
than the hind wings. The caterpillars have long and slender bodies
with the upper part of the head, when looked at from in front,
tapering rather than roundish or square. The chrysalids have the
tongue-case free at the tip and projecting beyond the tips of the
wing-cases.
=The Tawny-edged Skipper=
_Thymelicus cernes_
This is one of the commonest and most widely distributed of all our
Skippers. It is found from Nova Scotia to British Columbia, south
along the Rocky Mountains to New Mexico, Texas, and Florida. It is
apparently absent west of the Rocky Mountains and along the Gulf Coast
except in Florida. Its life-history was carefully worked out by Dr.
James Fletcher, late entomologist to the Dominion of Canada, and in
the north may be summarized thus: the butterflies come from the
hibernated chrysalids in May or June. They remain upon the wing for
several weeks so that worn specimens may be taken late in July or,
rarely, even early in August. The females lay eggs upon grass blades.
These eggs hatch about two weeks later, the larvae eating their way
out of the shells so slowly that a whole day may be taken up by the
operation. Each little caterpillar weaves a silken nest for itself, in
which it remains concealed most of the time, reaching out to feed upon
adjacent blades of grass but retiring into the nest at the least
alarm. It is a sluggish little creature and grows so slowly that in
the north it may require more than two months to become full fed as a
larva. It is then about an inch long and has the characteristic
outlines of the other Skipper larvae, with a black head and a greenish
brown body. It now spins a cocoon, possibly using its larval nest as
a basis, and some time later, before cold weather surely, it changes
to a chrysalis that winters over.
This is the story of the life of the butterfly in the more northern
parts of its range. Even in New Hampshire there seems to be at least a
partial second brood, and farther south there are probably two regular
broods with the possibility that a small percentage of the first set
of chrysalids remains unchanged until spring.
=The Roadside Skipper=
_Amblyscirtes vialis_
This little butterfly is found apparently in most parts of the United
States, as it has been collected in New England, California, Texas,
and many intermediate points. Over the northern part of its range
there is but one brood a year. In New Hampshire the butterflies appear
in May and early June and lay eggs upon the blades of various grasses.
These hatch about ten days later into slender, silk-spinning
caterpillars, each of which makes a nest for itself by sewing together
the margin of one or more grass blades. When the larvae get larger,
they make larger and denser nests with heavy linings of silken web.
After the earlier moults, the thin skin is covered with very fine
snow-white hairs, between which there is developed a curious whitish
exudation, so that the caterpillars have a flocculent appearance. When
full grown, they change to delicate green chrysalids which apparently
in the North remain until the following spring before disclosing the
butterflies. In more southern regions there are two broods each
summer.
=The Least Skipper=
_Ancyloxipha numitor_
The Least Skipper differs from the other Skippers both in structure
and habits. Most of these butterflies have thick bodies and a distinct
hook at the end of each antenna. This has a slender body and the
antennae lack the hook. Most Skippers have strong wings and show their
strength in their rapid, erratic flight. This has feeble wings that
show their weakness in their slow, straight flight. But from the fact
that it is about the smallest of all our butterflies, expanding little
more than three quarters of an inch, it deserves our interested
attention. The tawny wings are so marked with broad margins of dark
brown that they show the tawny tinge chiefly in the middle spaces.
On account of its small size and its retiring habits this little
butterfly is often overlooked by all but the most experienced
collectors. It generally flies slowly just above the grass in sunny
places in wet meadows and along the open margins of brooks and
marshes. It rests frequently upon grasses, flowers, or bushes. Mr.
Scudder noticed that when resting these butterflies have the curious
habit of "moving their antennae in a small circle, the motion of the
two alternating; that is, when one is moving in a forward direction,
the other is passing in a reverse direction." This is the sort of
observation that should challenge us all to sharper wits in watching
living butterflies. It would be strange if no others thus twirled
their feelers in their leisure moments. Who will find out?
The female butterflies at least have something to do besides sipping
the nectar of flowers or idly twirling their feelers. They must lay
their eggs and thus provide for the continuation of the species; to do
this they find suitable blades of grass on which they deposit their
tiny, half-round, smooth yellow eggs. A week or so later each egg
hatches into a dumpy little yellow caterpillar with a black head and a
body well covered with hairy bristles. This little creature is a silk
spinner and makes a home instinctively by drawing together more or
less the outer edges of a leaf blade and fastening them with
transverse bands of silk. It then feeds upon the green tissues and as
it grows larger it makes its nest more secure by thicker walls of
silken web.
When full grown as a caterpillar it changes into a slender chrysalis
generally of a grayish red color, thickly dotted with black. About ten
days later it emerges as a butterfly.
The Least Skipper is one of the most widely distributed of all
butterflies. It occurs from New England to Texas, south to Florida on
the east coast, and west to the Rocky Mountains.
THE END
GENERAL INDEX
Abdomen, 4
Acadian hair-streak, 248
Admiral, Red, 160
Aestivation, 21-22
_Agapetidae_, 214-229
_Aglais milberti_, 182
_Ajax_, 77
_Amblyscirtes vialis_, 280
American copper, 255
American tortoise-shell, 182
Anatomy of butterflies, 3-5
_Ancyloxipha numitor_, 281
Androconia, 15
Angle-wings, Synopsis of the, 190
Angle-wings, Tribe of the, 150-192
_Anoea andria_, 208
_Anosia berenice_, 235
_Anosia plexippus_, 233
Antennae, 3-4
_Anthocaris genutia_, 97
_Anthocaris olympia_, 97
Antiopa, 112-115, 171-182
Ants and caterpillar, 261
Aphids, 261
Apparatus for collectors, 51-54
_Araulis vanillae_, 115
Arctic satyr, 225
_Argynnis aphrodite_, 125
_Argynnis atlantis_, 126
_Argynnis cybele_, 122
_Argynnis diana_, 118
_Argynnis idalia_, 120
_Argynnis montinus_, 127
_Atlides halesus_, 243
Baltimore checker-spot, 135
Banded hair-streak, 246
Banded purple, 202
_Basilarchia archippus_, 195-202
_Basilarchia arthemis_, 202
_Basilarchia astyanax_, 204
_Basilarchia floridensis_, 206
Black-bordered yellow, 105
Black swallowtail, 59
Blue-eyed grayling, 215
Blue swallowtail, 65
Blues, Synopsis of the, 265
Blues, Tribe of the, 258-265
_Brenthis bellona_, 128
_Brenthis myrina_, 131
Brimstone butterfly, 98
Bronze copper, 257
Brown, Eyed, 221
Brown, Gemmed, 227
Buckeye, 188
Butterflies, Aestivation of, 21-22
Butterflies, Anatomy of, 3-5
Butterflies and Moths, Difference between, 13-14
Butterflies, Classifications of, 55
Butterflies, Collecting, 49-54
Butterflies, Coloration of, 24-35
Butterflies, feigning death, 22-23
Butterflies, General characteristics of 3-54
Butterflies, Hibernation of, 17-21
Butterflies, Migrations of, 16-17
Butterflies, Parasites of, 40-43
Butterflies, Photographing, 47-48
Butterflies, Rearing of, 43-47
Butterflies, Scents of, 15
Cabbage butterfly, Southern, 88
Cabbage butterfly, White or Imported, 83
_Callidrayas eubule_, 98
_Calosoma scrutator_, 181
_Calycopis cecrops_, 251
Camberwell beauty, _see_ Mourning-cloak
Carolina satyr, 227
Caterpillar cages, 44
Caterpillar collecting, 44
Caterpillar habits, curious, 198
Caterpillar hunter, 181
Caterpillar parasites, 260
Caterpillar to chrysalis, 8-10
Caterpillars, 5-9
_Catopsilia eubule_, _C. philea_, or _C. agarithe_, 109
_Cercyonis alope_, 215, 228
_Cercyonis pegala_, 218
Chalcid flies, 42
_Charidryas nycteis_, 141
Checker-spot, Baltimore, 135
Checker-spot, Harris's, 140
Checkered white, 88
_Chlorippe celtis_, 210
_Chlorippe clyton_, 212
Chrysalis, 8-12
Chrysalis to butterfly, 10-13
_Chrysophanus hypophlaeus_, 257
_Chrysophanus thoë_, 257
_Cinclidia harrisii_, 140
_Cissia eurytus_, 226
_Cissia sosybius_, 227
Classification of butterflies, 55
Clouded sulphur, 101
Cloudless sulphur, 98
_Colias caesonia_, 110
_Colias eurytheme_, 110
_Colias philodice_, 110
Collecting butterflies, 49-54
Color changes, 7
Color sense, Selective 32
Coloration, 24-35
Comma, 153
Common skippers, 268-282
Common wood nymph, 215
Compton tortoise, 185
Copper, The American, 255
Copper, The Bronze, 257
Coppers, Synopsis of the, 257
Coppers, Tribe of the, 252-258
Cosmopolite, 166-171
Counter-shading, 24-25
Cremaster, 8
Crescent-spots, Synopsis of the, 149
Crescent-spots, Tribe of the, 135-150
Cyanide bottle, 51
_Cyaniris ladon_, 258
_Cynthia atalanta_, 191
_Cynthia cardui_, 191
_Cynthia kuntera_, 191
Cynthia Moth, 14
Dainty sulphur, 109
Dazzling coloration, 26-29
Death-feigning, 22-23
_Debis portlandia_, 227
Diana fritillary, 118
Dog's-head butterfly, 100
Drying box, 54
Dull-eyed grayling, 228
Dusky-wing, Juvenal's, 272
Dusky-wing, Persius's, 276
Dusky-wing, Sleepy, 275
Eclipsing coloration, 26-29
Eclosion, 11
Egg-laying, 46
Emperors, Tribe of, 207-214
Encasement theory, 9
_Enodia portlandica_, 219
Envelopes for collectors, 52
_Epargyreus tityrus_, 270
_Euchloe genutia_, 97
_Euchloe olympia_, 97
_Eudamus proteus_, 271
_Eugonia J-album_, 185
_Euphydryas phaeton_, 135
_Eupsyche M-album_, 244
_Euptoieta claudia_ 116
_Eurema euterpe_, 111
_Eurema lisa_, 106
_Eurema nicippe_, 105
_Eurymus eurytheme_, 102
_Eurymus interior_, 104
_Eurymus philodice_, 101
_Euvanessa antiopa_, 191
_Everes comyntas_, 264
Exuviae, 6
Eyed brown, 221
Falcate orange-tip, 94
_Fenisequa tarquinius_, 253
Fritillaries, Synopsis of the, 133
Fritillaries, Tribe of the, 115-135
Gemmed brown, 227
Georgia satyr, 227
Giant skippers, 267-268
Giant swallowtail, 62
Goatweed emperor, 208
Gossamer-wings, 240-265
_Grapta comma_, 190
_Grapta faunus_, 190
_Grapta interrogationis_, 190
_Grapta J-album_, 192
_Grapta progne_, 191
Gray comma, 158
Gray emperor, 210
Gray hair-streak, 245
Gray-veined white, 86
Grayling, Blue-eyed, 215
Great purple hair-streak, 243
Great southern white, 90
Great spangled fritillary, 122
Green-clouded swallowtail, 67
Green comma, 159
Gulf fritillary, 115
Hair-streaks, Synopsis of the, 250
Hair-streaks, Tribe of the, 242-252
Harris's checker-spot, 140
Heliconians, 229-232
_Heliconidae_, 229-232
_Heliconius Charitonius_, 229
Heliotropism, 35-37
_Heodes hypophlaeus_, 255
_Hesperiidae_, 268-282
_Hesperioidea_, 55, 266-282
Hibernation, 17-21
Honey-dew, 261
Hop merchant, 153
_Hypatus bachmani_, 236
Ichneumon flies, 41-42
Imago, 10
Imported cabbage butterfly, 83
_Iphiclides ajax_, 76
_Junonia coenia_, 188
Juvenal's dusky-wing, 272
Killing bottle, 51
_Laertias philenor_, 65
Larger Skippers, Tribe of the, 269-278
Least purple hair-streak, 251
Least skipper, 281
_Lepidoptera_, _see_ Butterflies
_Libytheidae_, 236-239
_Limenitis arthemis_, 206
_Limenitis astyanax_, 207
_Limenitis disippus_, 207
List observations, 37-40
Little sulphur, 106
Little wood nymph, 228
Little wood satyr, 226
Locusts, Coloration of, 29
Long-beaks, The, 236-239
Long-tailed skipper, 271
_Lycaena comyntas_, 265
_Lycaena ladon_, 265
_Lycaena lygdamus_, 265
_Lycaena scudderi_, 265
_Lycaenidae_, 240-265
_Lymnadidae_, 232-236
_Marcellus_, 77
Maritime grayli
Meadow-browns, The, 214-229
Meadow fritillary, 128
_Meganostoma caesonia_, 100
_Megathymidæ_, 267-268
_Megathymus yuccae_, 267
_Melitaea harrisii_, _M. phaeton_, _M. nycteis_, _or_ _M. tharos_, 149
Metal-marks, The, 239-240
Microgaster, 42
Migrations, 16-17
Milkweed butterflies, The, 232-236
Mimicry, 34-35
_Mitoura damon_, 249
Monarch, The, 12, 233
Moths, 13-14
Moulting, 6-7
Mountain silver-spot, 126
Mourning-cloak, 112-115, 171-182
_Nathalis iole_, 109
_Neonympha canthus_, 227
_Neonympha eurytus_, 228
_Neonympha gemma_, 227
_Neonympha phocion_, 227
Net, Butterfly, 51
Nettle butterfly, 160
_Nomiades lygdamus_, 265
_Nymphalidae_, 111, 214
Nymphs, The, 111, 214
Odors, _see_ Scents of butterflies
_Oeneis norna jutta_, 225
_Oeneis norna semidea_, 222
Olive hair-streak, 249
Olympian orange-tip, 96
"Orange dogs", 63
Orange sulphur, 102
Orange-tips, Synopsis of the, 97
Orange-tips, Tribe of the, 92-97
Orientation, _see_ Heliotropism
Painted beauty, 163
Painted lady, 166-171
Palamedes swallowtail, 76
Palpi, 4
_Papilio asterias_, 81
_Papilio brevicauda_, 75
_Papilio cresphontes_, 80
_Papilio glaucus_, 72
_Papilio palamedes_, 76
_Papilio philenor_, 81
_Papilio polyxenes_, 59
_Papilio thoas_, 62
_Papilio troilus_, 67
_Papilionidae_, 57-81
_Papilionoidea_, 55, 265
Parasites, 40-43
Parasites of the Mourning-cloak, 177
Parnassians, 56-57
_Parnassiidae_, 56-57
Pearl crescent, 143
Pearly eye, 219
Persius's dusky-wing, 276
_Pholisora catullus_, 277
Photographing butterflies, 47-48
_Phyciodes nycteis_, 149
_Phyciodes tharos_, 143
_Pieridae_, 82-115
_Pieris napi_, 86
_Pieris phileta_, 92
_Pieris protodice_, 91
_Pieris rapae_, 83
Pink-edged sulphur, 104
Pins for collectors, 53
_Polygonia comma_, 153
_Polygonia faunus_, 159
_Polygonia interrogationis_, 150
_Polygonia progne_, 158
Polygonias, Synopsis of, 190
_Pontia monuste_, 90
_Pontia protodice_, 88
Protective coloration, _see_ Coloration
Purple hair-streak, Great, 243
Purple hair-streak, Least, 251
Purples, Banded and Red-spotted, 202-206
_Pyrameis atalanta_, 191
_Pyrameis cardui_, 191
_Pyrameis huntera_, 191
_Pyrrhanea andria_, 214
Queen, The, 235
Rearing butterflies, 43-47
Red Admiral, 160
Red-horns, Tribe of the, 97-115
Red-spotted purple, 204
Regal fritillary, 120
Riker mounts, 54
_Riodinidae_, 239-240
Roadside skipper, 280
_Rusticus scudderi_, 263
Satyr, Arctic, 225
Satyr, Little wood, 226
_Satyrodes canthus_, 221
Satyrs, The, 214-229
Satyrs, Georgia and Carolina, 227
Scents of butterflies, 15
Scudder's blue, 263
Selective color sense, 32-33
Setting board, 52-53
Shadow observations, 37-40
Short-tailed papilio, 75
Silver-bordered fritillary, 131
Silver crescent, 141
Silver-spot fritillary, 125
Silver-spotted skipper, 270
Silvery blue, 265
Skippers, 55, 266-282
Skippers, Common, 268-282
Skippers, Tribe of the larger, 269-278
Skippers, Tribe of the smaller, 278-282
Sleepy dusky-wing, 275
Smaller skippers, Tribe of the, 278-282
Snout butterflies, The, 236-239
Sooty wing, The, 277
Southern cabbage butterfly, 88
Southern wood nymph, 218
Sovereigns, Synopsis of the, 206
Sovereigns, Tribe of the, 192-207
Spring azure, 258
Striped hair-streak, 247
Sulphur butterflies, 98-100, 101-105, 106-109
Swallowtails, 57-81
Swallowtails, Synopsis of, 80
_Synchloe genutia_, 94
_Synchloe olympia_, 96
Tachina flies, 42-43
Tailed blue, 264
Tawny-edged skipper, 279
Tawny emperor, 212
_Telamonides_, 77
_Terias lisa_, 110
_Terias nicippe_, 110
_Thanaos brizo_, 275
_Thanaos juvenalis_, 272
_Thanaos persius_, 276
_Thecla acadica_, 248
_Thecla calanus_, 246
_Thecla cecrops_, 251
_Thecla damon_, 252
_Thecla halesus_, 250
_Thecla liparops_, 247
_Thecla M-album_, 251
_Thecla melinus_, 251
Thistle butterfly, 166-171
Thorax, 4
_Thymelicus cernes_, 279
Tiger swallowtail, 72
Tortoise-shell, American, 182
Transformations, 5-13
_Uranotes melinus_, 245
_Vanessa antiopa_, 171-182
_Vanessa atalanta_, 160
_Vanessa cardui_, 166-171
_Vanessa coenia_, 192
_Vanessa huntera_, 163
_Vanessa J-album_, 192
_Vanessa milberti_, 191
Vanessids, Synopsis of, 191
Variegated fritillary, 116
Vicereine, 206
Viceroy, 195-202
Violet-tip, 150
Wanderer, The, 253
Warning coloration, 33-34
Weismann's theory, 10
White cabbage butterfly, 83
White J butterfly, 185
White M hair-streak, 244
White Mountain butterfly, 222
White Mountain fritillary, 127
Whites, Synopsis of the, 91
Whites, Tribe of the, 82-92
Wing expansion, 12-13
Wood nymph, Little, 228
Wood nymphs, 215-218
_Xanthidia lisa_, 110
_Xanthidia nicippe_, 110
Yellow edge, _see_ Mourning-cloak
Yellows, Synopsis of the, 109
Yellows, Tribe of the, 97-115
Yucca-borer skipper, 267
Zebra butterfly, 229
Zebra swallowtail, 76
_Zerene caesonia_, 110
Transcriber's Notes
Except for the list of corrections below and minor corrections
(deletion or addition of periods or commas; application of styling
to headers to match comparable divisions; etc.), the text presented
is that contained in the original printed version. Any unique
grammatical usage has been retained. Some of the illustrations were
moved so that paragraphs were not split. Also, some of the text in
the illustration blocks were rearranged so that they more closely
matched each other.
Although in there are chacters available for some common fractions
diplayed in this text (ex., ¼, ½ and ¾), other fractions (ex., 1/3;
1/5, etc.) are not available. Therefore, it was decided to display
them all in the format #/#. In the case of mixed fractions, they are
displayed as # #/# (ex., 3 1/2).
Typographical Corrections
Page Correction
===== ====================
146 similiar => similar
156 harrisi => harrisii
194 eing => being
262 analagous => analogous
284 Heleconidae => Heliconidae
283 c. philea => C. philea
283 c. agarithe => C. agarithe
" Cercyonis alope 215-228 => 215, 228
285 Monarch, The 12-223 => 12, 233
" Nymphalidae 111-214 => 111, 214
" Nymphs, The 111-214 => 111, 214
" Papilionoidea 55-265 => 55, 265
Emphasis Notation
_Text_ - Italic
=Text= - Bold
End of Project Gutenberg's Butterflies Worth Knowing, by Clarence M. Weed
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