142 Twenty-third Report on the State Cabinet. 



Yoimg Larvce. — When first escaped from the shell, they are of a 

 pale reddish-brown color, which gradually changes in the course of 

 a few hours to fuscous. Their length is .13 of an inch. Under a high 

 niafi-nifying power, the larva appears as follows : The head is shining 

 black and bears a few whitish hairs of the length of about one-half its 

 diameter; its dimensions taken from the case after its molt are, length 

 .032 of an inch, breadth .03 of an inch. The body is glossy black 

 with minute granulations dorsally and laterally, reddish-brown and 

 smooth ventrally. Its armature consists of eight rows of spines on 

 the anterior segments (varying from five to eight rows on the other 

 segments as stated hereafter) which are glossy black, subcylindrical, 

 muricate, in length nearly equaling the diameter of the larva, giving 

 out at the apex four diverging spinules and a curved ciliated bristle of 

 nearly double the length of the spine. The spines of the three anterior 

 segments in the six superior rows are forked at about their apical 

 fourth, with each fork bearing its spinules and bristle as above. The 

 anal plates of the larva have on them a few black hairs. 



There being no food at hand, the larvne collected in a body in an 

 angle of the box in wliich they were confined. The following day the 

 colony was several times observed in motion, probably in quest of food, 

 in regular procession of two or three abreast. On the 30th, after their 

 refusal of a half dozen species of leaves, oak-leaves M-ere given them, 

 and upon these they immediately commenced to feed vigorously. 

 Beginning at the margin of a leaf, they ate inwardly, consuming in 

 their progress even the larger veinlets, but not the midrib except at its 

 tip. On the 2d of June, they had collected in three clusters — two 

 on separate leaves and the third on a twig — and had assumed their 

 position for molting on a slight web spun beneath them, in which the 

 booklets of their anal legs were firmly implanted. 



First molt. — On the morning of the 4th of June, they were found to 

 have undergone this change during the night. Their cast skins 

 (exuviie) were adhering to the surface to wliich the larvae had been 

 attached, and had not been fed upon by them ; the detached head-cases 

 were strewn over the bottom of the box. They now measui-e three- 

 tenths of an inch in length. The head is shining black, with a few 

 black hairs. The body is blackish, and when highly magnified, 

 granulated. The spines are glossy black, with three or more branches, 

 in the truncated tips of which are inserted a bristle of about one-third 

 the length of the spine. The spines of the two anterior segments are 

 longer than the others; on segments three to seven inclusive in the two 

 superior rows, the main spine (which is trifid on segment three, biliil 

 on segment four and simple on segments five to seven) is acutely ter- 



