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Show 1900.] INSECTS OF THE " SKEAT EXPEDITION." 85l mosses of the minutest size; so that large Locustids of yellows green, Pseudophgllus and others, which in the cabinet, and perbap-in their o w n place, form such admirable imitations of bamboo-leaves in colour, and to a lesser degree in form also (for doubtless they are part of theplancton of tbe jungle, and only gravitate down into its depths by misadventure), are the most conspicuous of the smaller jungle fauna which one meets with below. Yet all these shades are so altered and commingled in the chequer of deep shadow with occasional gleams of sunlight that they become completely confused to the eye. One is tempted to speculate as to whether the gorgeous tartan-like checks in which the Malays are so fond of clothing themselves may not have originally developed among a jungle-loving and somewhat murderous people at constant feud with their neighbours, as a means of secondary protective coloration, and have become more brilliant and less useful through the vagaries of sexual selection. O n festive occasions these combinations of many colours are chiefly worn by the men, the women preferring for their holiday dresses simpler and more striking costumes into which only four or five masses of colour enter as a rule. On the jungle floor itself the most inconspicuous animals are certain long-legged but by no means bulky Phalangiids, w7hich appear and disappear as they move or are still. Intrinsically they are of brilliant colours ; one species is black, speckled on the body and limbs with scarlet, white, yellow, and green. But they are less conspicuous even than the majority of Phasmids found in similar situations, even than the forms which have green markings resembling minute liverw7orts, such as cover the stems and leaves of the jungle flora, on their otherwise stick-like bodies ; for it is generally easy to distinguish the exact outlines of such insects if they have once been located; but even when the Phalangiids are moving it is rarely possible to see either their limbs or their bodies, though their motions are perfectly visible. Every such stick-insect resembles a particular stick, an ideal stick it is true; the Arachnids are assimilated, not to any particular object, but to their surroundings generally, by their irregular colour, their irregular form, and by the large extent of their surface in comparison with their bulk. The limbs of the Phasmids are often held in angular vegetable attitudes, but they do not always blend into their environment as the almost hair-like legs of the Phalangiids do; for it is often the case that the instinct of the insects is at fault in the choice of their immediate surroundings *, whereas the protective adaptation of the Arachnids, being general and not particular, does not necessitate any high specialization of instinct to accompany it. But that the object of brilliant coloration arranged in stripes is not always the same, even in a single group of insects, is proved, if proof were necessary, by comparing the striped pupa from Aring with the Arabian and African imago Idolum diabolicum2, a form of which the natural colour and attitude have lately been described 1 See Proc. Roy. Phys. Soc. Edinburgh, Dec. 1900. 2 P. Cambr. Phil. 8oc. vol. x. p. 175 et post., plate ii. PROC. ZOOL. Soc-1900, No. LVI. 56 |