252 



THE STUDY OF INSECTS 



. 



on the body are small, of a reddish color with metallic reflections. The 



cocoon (Fig. 442) is dense and usually 

 enclosed in a leaf; it can be uti- 

 lized for the manufacture of silk. 

 When the adult is ready to emerge, 

 it excretes a fluid which softens the 

 cocoon at one end, and breaking 

 the threads by means of a pair of 

 stout spines, one on each side of the 

 thorax at the base of the fore wings, 

 it makes its exit through a large 

 round hole. 

 The Luna-moth, Tropcea luna. — This magnificent moth (Fig. 443) is 



a great favorite with amateur collectors. Its wings are of a delicate light 



green color, with a purple-brown band on the costa of the fore wings; 



there is an eye-like spot with a transparent center on the discal vein of 



Fig. 442. — Cocoon of Telea polyphemus. 



Fig. 443. — Tropcra luna. 



each wing; and the anal angle of the hind wings is greatly prolonged. 

 The larva feeds on the leaves of walnut, hickory, and other forest-trees. 

 It measures when full-grown about 3 inches in length. It is pale bluish 

 green with a pearl-colored head. It has a pale yellow stripe along each 



