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would not let me approach, and kept running away round and round their pole, so I threw the insect at them. Their fright was ludicrous to see; with loud cries they jumped aside and clambered up the pole as fast as they could go, into their box, where they sat peering over the edge watching the uncanny object below." (Marshall.)

Marshall also writes concerning the markings on the wings of the mantis, Pseudocreobotra wahlbergi:

"They are, I think, almost certainly of a terrifying character. When the insect is irritated, the wings are raised over its back in such a manner that the tegmina stand side by side, and the markings on them present a very striking resemblance to the great yellow eyes of a bird of prey or some feline animal, which might well deter an insectivorous enemy. It is noticeable that the insect is always careful to keep the wings directed toward the point of attack, and this is often done without altering the position of the body."

Still another use is believed by some entomologists to be afforded by such markings as ocelli and other specially conspicuous spots and flecks on the wings of butterflies and moths, and by such apparently useless parts as the "tails" of the hind wings of the swallowtail, and Lycanid butterflies, and others. Marshall occupied himself for a long time with collecting butterflies which had evidently been snapped at by birds (in some cases the actual attack being observed) and suffered the loss of a part of a wing. Examining these specimens when brought together, Poulton and Marshall noted that the "great majority [of these injuries to the wings] are inflicted at the anal angle and adjacent hind margin of the hind wing, a considerable number at or near the apical angle of the fore wing, and comparatively few between the points." In this fact, coupled with the fact that the apical and hind angles of the fore and hind wings respectively are precisely those regions of the wings most usually specially marked and prolonged as angular processes or tails, Poulton sees a special significance in the patterns of these wing parts. He thinks they are "directive marks which tend to divert the attention of an enemy from more vital parts." It is obvious that a butterfly can very well afford to lose the tip or tail of a wing if that loss will save losing head or abdomen. Poulton sees a "remarkable resemblance of the marks and

structures at the anal angle of the hind wing, under side, in many Lycanida, to a head with antennæ and eyes," and recalls that this has been independently noticed by many other observers. The movements of the hind wings by which the tails, which appear like antennæ, are made continually to pass and repass each other, add greatly to this resemblance.

Very many species of animals, especially among the vertebrates, possess certain distinctive and striking markings, which

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FIG. 262.—The butterfly fish, Chetodon vagabundus. from Samoa. This small fish is most strikingly colored.

have been supposed to serve as recognition marks to other animals of the same species. In this theory, these marks afford a swift means of knowing friends from enemies. Of this nature are the white tufts at the tail of the cottontail rabbit, the black patch of the blacktail deer, the flanks of the Rocky Mountain antelope, the concealed scarlet crest of the kingbird, the fiery shoulder of the redwing blackbird, the blue speculum of the duck, the black bars and eye spots of the butterfly fishes (Chatodon), and the peculiar marks of one form or another on a host of mammals, birds, reptiles, and fishes.

It is very easy to indicate recognition marks. Keeler, among others, has given an elaborate list of the principal cases among American birds, and there is scarcely a species without one or

more. Nevertheless we are not sure that many, or even any of them, actually serve the purpose of recognition among the animals themselves, however convenient they may be to us who study them. However plausible the theory of recognition marks may seem, it is still not proved to have any objective basis.

Of all the theories accounting for the utility of color and pattern, that of mimicry demands at first thought the largest degree of credulity. As a matter of fact, however, the observation and evidence on which it rests are as convincing as are those for almost any of the other forms of protective color pattern. Although the word "mimicry" could often have been used aptly in the account of special protective resemblance, it has been reserved for use in connection with a specific kind of imitation; namely, the imitation by an otherwise defenseless insect, one without poison, beak, or sting, and without acrid and distasteful body fluids, of some other specially defended or inedible kind, so that the mimicker is mistaken for the mimicked form and, like this defended or distasteful form, relieved from attack. Many cases of this mimicry may be noted by any field student of entomology.

Buzzing about flowers are to be found various kinds of bees, and also various other kinds of insects thoroughly beelike in appearance, but in reality not bees nor, like them, defended by sting. These bee mimickers are mostly flies of various families (Syrphide, Asilide, Bombyliida), and their resemblance to bees is sufficient to and does constantly deceive collectors. We presume, then, that it equally deceives birds and other insect enemies. Wasps, too, are mimicked by other insects; the wasplike flies, Conopida, and some of the clearwinged moths, Sesiidae are extremely wasplike in general seeming.

The distasteful monarch butterfly, Anosia plexippus, widespread and abundant-a successful butterfly, whose success undoubtedly largely depends on its inedibility in both larval and imaginal stages-is mimicked with extraordinary fidelity of detail by the viceroy, Basilarchia archippus (Fig. 263). The Basilarchias, constituting a genus of numerous species, are with but two or three exceptions not at all of the color or pattern of Anosia, but in the case of the particular species archippus, not only the red-brown ground color, but the fine pattern

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FIG. 263. The mimicking of the inedible monarch butterfly by the edible viceroy. The figure at the top is the monarch, Anosia plexippus. The middle figure is the viceroy, Basilarchia archippus. The lowest figure is another member of the same genus, Basilarchia, to show the usual color pattern of the species of the genus.

details in black and whitish, copy faithfully the details in Anosia; only in the addition of a thin blackish line across the discal area of the hind wings does archippus show any noticeable difference. The viceroy is believed not to be distasteful to birds, but its close mimicry of the distasteful monarch undoubtedly leads to its being constantly mistaken for it by the birds and thus left unmolested.

The subject of mimicry has not been studied largely among the insects of our country, but in the tropics and subtropics numerous striking examples of mimetic forms have been noted and written about. The members of two large families of butterflies, the Danaidæ and Heliconidæ, are distasteful to birds, and are mimicked by many species of other butterfly families, especially the Pieridæ, and by the swallowtails, Papilionidæ. Many plates illustrating such cases have been published by Poulton and Marshall, Haase, Weismann, and others. Shelford, in an extended account of mimicry as exemplified among the insects of Borneo, refers to and illustrates many striking examples among the beetles, the Hemiptera, Diptera, Orthoptera, Neuroptera, and moths; distasteful Lycid beetles are closely mimicked by other beetles, by Hemiptera, and by moths; distasteful ladybird beetles are mimicked by Hemiptera, Orthoptera, and by other beetles; stinging Hymenoptera are mimicked by stingless Hymenoptera, by beetles, flies, bugs, and moths. Poulton and Marshall, in their account of mimicry among South African insects, publish many colored plates revealing most striking resemblances between insects well defended by inedibility or defensive weapons, and their mimickers. Our space unfortunately prevents any specific consideration of these various interesting cases.

The special conditions under which mimicry exists have been seriously studied and are of extreme interest. It is obvious that the inedible or defended mimicked form must be more abundant than the mimicker, so that the experimenting young bird or lizard may have several chances to one of getting an ill taste or a sting when he attacks an insect of certain type or pattern. This requirement of relative abundance of mimicker and mimicked seems actually met, as proved by observation. In some cases only females of a species indulge in mimicry, the males being unmodified. This is explained on the ground of the particular necessity for protection of the egg-laden, heavy

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