17 



in summer ou the wing, searching 

 When found she watches her oppor- 



Fig. 10 



This lovely creature flies only at night, and when on the wing is of such a size that 

 it is often mistaken in the dusk for a bat. Within a few days the female deposits her 

 eggs, glueing them singly to the under side of the leaves, usually one only on a leaf, but 

 occasionally two or even three may be found on the same leaf. 



The egg is about one-tenth of an inch in diameter, slightly convex above and below, 

 the convex portions whitish, and the nearly cylindrical sides brown. Each female will 

 lay from two to three hundred eggs, which hatch in ten or twelve days. 



This insect is subject to the attack of many foes, particularly while in the larval 

 state. A large number fall a prey to insectivorous birds, and they also have insect 

 enemies. A large ichneumon fly, Ophion macrurum, see fig. 11, is a special and danger- 

 ous foe. This active creature may often be seen 

 among the leaves of shrubs and trees for her prey, 

 tunity, and places quickly upon the skin of her vic- 

 tim a small oval white egg, securely fastened by a 

 small quantity of glutinous substance attached to 

 it. This is repeated until eight or ten eggs are 

 placed, which in a few days hatch, when the tiny 

 worms pierce through the skin of the caterpillar 

 and begin to feed on the fatty portions within. The 

 Polyphemus caterpillar continues to feed and grow, 

 and usually lives long enough to make its cocoon, 

 when, consumed by the parasites, it dies ; in the 

 meantime the ichneumons, having completed their 

 growth, change to chrysalids within the cocoon, 

 and in the following summer, in place of the hand- 

 some moth there issues a crop of ichneumon flies. 

 It is also subject to the attacks of another parasite, 

 a tachina fly. Should the insect ever appear in 

 sufficient numbers to prove troublesome, it can be 

 readily subdued by hand-picking. This larva feeds on a variety of trees and shrubs, 

 such as plum, oak, hickory, elm, basswood, walnut, maple, butternut, hazel, rose, &c. 



As this moth has been found to be easily propagated, extensive experiments have 

 been tried with the view 'of producing silk for commercial purposes from the cocoons. 

 The silk is rather coarser than that of the common silk worm, Bombyx mori, has a con- 

 tinuous thread and can be readily unwound. A measure of success has attended these 

 2 (D.) 



