THE CATERPILLAR
“The newly emerged larva does not venture far from the egg-shell and does not move about much for the first five or six hours. It sometimes devours the shell, but this is not usually the case. At the age of six hours it appears darker, and the black spots from which the hairlike spines protrude have become more conspicuous. Has not eaten any of the leaf, and has increased in size very little if at all.”
“At the age of twenty-seven hours the larva attains a length of 2.3 mm. and has eaten several small holes in the center of a large leaf, gnawing through the leaf to the transparent epidermis on the opposite side, which is left intact. Usually works from the upper side, but by no means invariably.”
“These smaller larvae seem to be always attached to the leaf with silk, although the threads are very few and fine. More mature larvae feed differently; they grip the petiole with the prolegs, and eat from the edge inward and forward, swinging the head toward the midrib, with practically no lateral motion.”
“The caterpillar is cylindrical and bears six rows of black, branching spines, twelve in each row. As regards color, there are besides the reddish, newly hatched creature described above, two well-defined types: the orange-drab and the drab-orange. In the first the body appears orange with three narrow drab stripes, and a very narrow lateral line just above the prolegs. In the second the drab markings become very much more prominent, so that the body now appears drab with four narrow orange stripes. The narrow drab dorsal line of the younger caterpillar becomes very conspicuous in the mature larva, separating the dorsal surface into two distinct orange areas. As the orange-drab type seems to embrace all of the smaller larvae, and as all those about to pupate belong to the drab-orange type, I have assumed that the color change is a matter of maturity.”