2 Journal New York Entomological Society. [Vol. xvi. 



Note. — Later in the month I took several masses of eggs on the 

 food plant. They were laid indifferently on either side of the leaf but 

 always near the apex. Of six masses counted the number varied from 

 90 to 180, there being more than 800 in the six masses. 



August 2. The two moths in the cage are dead. No change 

 noted in the egg. 



August 16. The eggs laid July 29 hatched this morning early. 

 Only two eggs failed to hatch. The little caterpillars are light green, 

 or greenish yellow in color, with large black heads. In leaving the 

 egg they eat out the top, leaving a round hole. 



August 17. The young larvae are eating out the upper epidermis 

 and parenchyma of the leaf through to the lower skin. They are hud- 

 dled together in a rather compact mass. All are quite lively. 



August 18. Very little change since last observation. Head shiny 

 black, body yellow-green, excreta greenish and collected in small 

 masses on the leaves and held together by a fine silky web. The sur- 

 face of the leaf over which they have fed is covered by a web. 



August 19. The little caterpillars have increased to about double 

 the size at hatching. Just back of the head is a transverse black spot 

 or plate from which rises several long white hairs, the whole having 

 the appearance of a collar. At the anal end are two blackish tubercles 

 (probably anal feet) from each of which arises a star of hairs or spines 

 some four or five in number. The whole body is more or less covered 

 with white hairs. The latter half of the body is of a pinkish color. 



August 20. Bodies becoming red. Four well-defined yellow 

 lines have appeared on each side of the body, extending from the head 

 to the anal extremity. They are feeding rapidly, generally on the 

 upper side of the leaf, leaving the veins and the lower epidermis intact. 



Note. — I have noticed that the young larvae feeding out of doors 

 always feed on the upper side of the leaf, and have judged that the 

 selection of this particular surface is due to the fact that in this species 

 of Rhus the leaves are inclined to fold along the midrib bringing the 

 upper surface of each side together, so that the little caterpillars are 

 afforded a measure of protection. 



An interesting habit was noticed to-day for the first time. When 

 slightly disturbed, the larvae raise the head and strike downward and 

 to one side, bringing the head nearly to the surface of the leaf. This 

 striking is done nervously but in strict time, the whole colony per- 

 forming together. 



