HICKORY. LEAVES HICKORY TUSSOCK-MOTH. 161 



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

 a short distance aside. When readyto cast its sidn it fixes itself to 

 the surface of the leaf by means of the minute sharp hoolis 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 placu 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, wUh 

 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 cat- 

 erpillar, the last much contracted in its length, being 

 taken from a dried cabinet 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 anterior two being nearer each other, and 

 upon each side is a row of three equidistant 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 roiv 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 long 

 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 crescent- 

 ghaped 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 white, 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 



11 



