CATERPILLAR AND THE MOTH
to times when our ancestors lived as individuals irre- sponsible one to another. The tent caterpillars ordinarily shed their skins six times during their lives. At each molt the skin splits along the middle of the back on the first three body seg- ments and around the back of the head. It is then pushed off over the rear end of the body, usually in one piece, though most other caterpillars cast off the head covering separate from the skin of the body in all molts but the last. The moltings take place in the tent, except the molt of the caterpillar to the pupa, and each molt renders the caterpillars inactive for the greater part of two davs. When most of them shed their skins at the same time there results an abrupt cessation of activity in the colony. By the rime the caterpillars reach maturity the discarded skins in a tent outnumber the caterpillars rive to one. The first stage of the caterpillars, as already described (Fig. 144 D), suggests nothing of the color pattern of the later stages, but in Stage II the spots and stripes of the mature caterpillars begin to be formed. In succeeding stages the characters become more and more like those of the sixth or last stage (Plate 14 D, Fig. I48), when the colors are most intensified and their pattern best defined. Particularly striking now are the velvety black head with the gray collar behind; the black shield of the first seg- ment split with a medium zone of brown; the white stripe down the middle of the back; the large black lateral blotches, each inclosing a spot of silvery bluish white; the distinctly bluish color between and below the blotches; and the hump on the eleventh segment, where the median white line is almost obliterated by the crowding of the black ffom the sides. Yet the creatures wearing all this lavishness of decoration make no ostentatious show, for the colors are all nicely subdued beneath the long reddish- brown hairs that clothe the body. In the last stage, the average full-grown caterpillar is about two inches long,
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INSECTS
