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Show 210 DARWINISM CHAP. bcina erected so as to produce a rude resemblance to the ~gu~c f 0 h' h the name of the family. The protection_ IS 0 a sp mx, once h fi h carn·e d f ur thc r by those species which retra.c t t e rst t rcc segmen t s an d have lar(oJ'e ocelli on cn.ch hs1 de hof ft he four thf segmen t , thus oo· ivin<Yo to the caterpillar, w en t c orcpart o 1 · th . ,. t its body is elevated, the n.ppcarance of a sna w m a I ca. cn-ing attitude. The blood-red forked tentacle, thrown out ~f the neck of the larvre of the <Ycnus Papilio when alarmed, Is, no doubt, a protection against the attacks of ichneumon~, and ma:y, perhaps, also frighten small birds; and the habit of turu~n.g np the tail possessed by the harmless. rove-beetles (Staphylu~ld:a'), giving the idea that they can stmg, h~, probably, a sn:mlar use. Even an unusual angular form, hkc a crooked tw1~ or inorgn.nic substance, may be protecti:c; as Mr. Poulton t~mk::; is the case with the curious caterpillar of N otodon~a z1czac, which by means of a few slight protuberances on Its body, is abie to assume an angular and very unorganic-lookin.g appearance. But perhaps the most perfect example ~f this kind of protection is exhibited by the lar~e caterpi~lar of the Royal Persimmon moth (Bom~yx reg1a), a native of the southern states of North Amenca, and known there as the "Hickory- horned devil." It is a larf?e gree~ caterpillar, often six inches long, orn~men~ed .w1th an ~mmcnsc crown of ora.n<Ye-rcd tubercles, whwh, If disturbed, It ereds and shakes fr;'m side to side in a very alarming manner. In its native country the negroes believe it to be as deadly as a rattlesnake, whereas it is perfectly. innocuous. The green colour of the body suggests tha.t Its ancestors were once protectively coloured; but, grow~ng too ~arg~ to lw effectually concealed, it acquired the habit ~f shakmg I~s bend about in order to frighten away its enenucs, and ~ltnnat.e.ly developed the crown of tentacles as an additio~ to Its terrl fying powers. This species is beautif~lly figured m Abbott anu Smith's Lepidopterous Insects of Gwrgta. A llU?·ing Coloration. Besides those numerous insects which obtain protection through their resemblance to the natu.ral ~bje?ts among wbic~ they live, there are some whose disgUise IS not used for vrn ORIGIN AND USES OF COLOUR IN ANIMALS 211 concealment, but as a direct mcn.ns of securing their prey by n.ttracting them within the enemy's ren.ch. Only a few cases of this kincl of coloration have yet been observed, chiefly among spiucrs and mantidre; but, no doubt, if attention were given to the subject in tropical countries, many more would be discovered. Mr. H. 0. Forbes has described a most interesting example of this kind of simulation in .Java. While pursuing a large butterfly through the jungle, he was stopped by a dense bush, on a leaf of which he observed one of the skipper butterflies sitting on a bird's dropping. "I had often," he says, "observed small Blues at rest on similar spots on the ground, and have wondered what such a refined and beautiful family as the Lycrenidre could find to enjoy, in food appn.l'ently so incongruous for a butterfly. I appron.chcd with gentle steps, but ready net, to see if possible how tho present species was engaged. It permitted me to get quite close, and even to seize it between my fingers ; to my surprise, however, part of the body remained behind, adhering as I thought to the excreta. I looked closely, and finally touched with my finger the excreta to find if it were glutinous. To my delighted astonishment I found that my eyes had been most perfectly deceived, and that what seemed to be the excreta was a most artfully coloured spider, lying on its back with its feet crossed over and closely adpresscd to the body." Mr. Forbes then goes on to describe the exact appearance of such excreta, and how the various parts of the spider are coloured to produce the imitation, even to the liquid portion which usually runs a little down the leaf. This is exactly imitated by a portion of tho thin web which the spider first spins to secure himself firmly to the leaf; thus producing, as Mr. Forbes remarks, a living bait for butterflies and other insects so artfully contrived as to deceive a pair of human eyes, even when intently examining it.I A native species of spider (Thomisus citrcus) exhibits a somewhat similar alluring protection by its close resemblance to buds of the wayfaring tree, Viburnum lantana. It is pure creamy-white, the abdomen exactly resembling in shape and colour the unopened buds of the flowers among which it takes 1 A Naturalist's Wande1·ings in the Euste?"'t .A1·chipelago, p. 63. |