Chapter X: Part II: The True Butterflies (4)

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.

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."

MONARCH BUTTERFLY IN RESTING POSITION]

FLASHLIGHT PHOTOGRAPH OF MONARCH OR MILKWEED BUTTERFLIES
IN MIGRATION]

The American Tortoise-shell (_see page 182_)
The Red Admiral (_see page 160_)
The Violet-tip (_see page 150_)]

The American Tortoise-shell (_see page 182_)
The Red Admiral (_see page 160_)
The Violet-tip (_see page 150_)]

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 aerial 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.

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_)]

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.

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.