HICKORY. LEAVES HICKORY TUSSOCK-MOTH. 1G1 



those of one of its comrades, he too stops feeding and moves at least 

 a short distance aside. When ready to cast its skin it fixes itself to 

 the surface of the leaf by means of the minute sharp hooks of its 

 feet; its exterior skin separates, and through a cleft at its anterior 

 end the worm crawls from it, leaving the empty skin with its 

 white and black tufts and pencils of hairs adhering to the leaf, 

 with the legs, particularly the pair at the extremity of the body 

 spread widely apart. They cast their skins three 

 times in attaining their growth. The accompany- 

 ing cut gives a view of these cast skins at each of 

 the moultings, and shows the increase which takes 

 place in the size of the caterpillar during the inter- 

 vals. With each change of its skin a very perceptible alteration 

 takes place in the appearance of the caterpillar. Its hairs, which 

 at first are so fine as to be scarcely noticed by the naked eye, be- 

 come so coarse and numerous at last as to hide from view the 

 skin and the dots with which it is ornamented. 



The Larva or caterpillar is sixteen footed, cylindrical, clean, clear white, 

 with numerous black dots, and clothed with tufts and longer pencils of hairs, 

 which are beautifully branched or bearded, and of a white color, interspersed 

 with other tufts and pencils which are black, the longest of the pencils being 

 half as long as the body. The accompanying figures 

 present a dorsal and lateral view of the young, and a 

 dorsal view of the mature caterpillar, the last much 

 contracted in its length, being taken from a dried cabi- 

 net specimen. On the anterior segments, the black dots 

 are arranged in a transverse row; on each of the others 

 there are four black dots above, at the angles of an imaginary square, the ante- 

 rior two being nearer each other, and upon each side is a row of three equidis- 

 tant dots, the upper one larger, with three minute black dots slightly below it, 

 and a short black stripe back of it. From each of these dots arises a tuft of 

 white or black hairs, there being a row of eight black tufts along the back, the 

 ends of which converge in the form of a steep roof, and two pencils of long 

 black hairs on the fourth and also on the tenth segments. Some Ion"' white 

 hairs overhang the head, which is black, smooth and shining, the bases of the 

 feelers and of the jaws and upper lip being white. The neck has a large cres- 

 cent-shaped spot above, placed transversely, and two small black dots on each 

 side, with two larger ones anteriorly below these. The legs are black, the 

 prolegs whjte, with a large black spot on their outer sides. 



The caterpillars attain their full size in about two months, and 

 are then nearly an inch and a half in length. Before they are 

 half grown they scatter themselves and thenceforth live apart and 



[Assem. No. 215.] 11 



