ATTACKING THE LEAVES. 175 



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. 



Remedies. 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. 

 An Ichneumon fly, Ophion macrurum, the same as that 

 which preys on the Cecropia emperor moth, No. 28 (see Fig. 

 73), is a special and dangerous foe. This active creature 

 may often be seen in summer on the wing, searching among 

 the leaves of shrubs and trees for her prey. When found, 

 she watches her opportunity, and places quickly upon the 

 skin of her victim a small oval white egg, securely fastened 

 by a small quantity of a glutinous substance attached to it. 

 This is repeated until several eggs are placed, which in a few 

 days hatch, when the tiny worms attach themselves to the 

 skin of the caterpillar and feed on the juices of their vic- 

 tim. 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 mean time 

 the Ichneumons, having completed their growth, change 

 to pupae within the cocoon, and in the following summer, 

 in place of the handsome moth, there issues a crop of Ich- 

 neumon flies. The polyphemus caterpillar 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. Besides the 

 plum, the larva feeds on a variety of trees and shrubs, such 

 as oak, hickory, elm, basswood, walnut, maple, butternut, 

 hazel, rose, etc. 



