stands out bare and dry. As the little thing advances it cuts up much more of the leaf than it eats, and these crumbs, with other refuse, are gradually accumulated, and loosely bound together with silk till they form a breastwork across the whole breadth of the leaf. Behind this rampart of refuse, of which its brown and ragged form seems to be a portion, the little architect lives, pushing the work back from day to day as it eats on."[1] Kirby and Spence pointed out many instances of the same active and intelligent mimicry. "Of this description is a little water-beetle (Elophorus aquaticus), which is always found covered with mud, and so when feeding at the bottom of a pool or pond can scarcely be distinguished by the predaceous aquatic insects from the soil on which it rests. Another very minute insect of the same order (Limnius æneus), that is found in rivulets under stones and the like, sometimes conceals its elytra with a thick coating of sand that becomes nearly as hard as stone." "A species of a minute coleopterous genus (Georyssus areniferus), which lives in wet spots where the Toad-rush (Juncus bufonius) grows, covers itself with sand; and another nearly related to it (Chætophorus cretiferus, K.), which frequents chalk, whitens itself all over with that substance. As this animal when clean is very black, were it not for this manœuvre it would be too conspicuous upon its white territory to have any chance of escape from the birds and its other assailants."[2]
Many examples of active mimicry are exhibited by our British moths, as may be learned by consulting the pages of Mr. Barrett's excellent work on the 'Lepidoptera of the British Islands.' Thus Eriogaster lanestris is an instance, for "even when sitting on a hawthorn spray it so accurately mimics a dead leaf twisted round the twig that it becomes almost impossible of recognition."[3] Cerura furcula sits in the daytime "on the trunk, or more usually on a branch, of one of its food-trees, its outstretched downy legs and grey markings giving it a most deceptive likeness to an entangled downy feather, or even a more close resemblance to a ripe sallow catkin from which the downy seeds are bursting."[4]
