THE BUTTERFLIES AND MOTHS 105 



threads that commonly protect them may be called cocoons 

 at all. A short time later they change again to adult 

 moths. 



The special danger from these Gypsy Moths is due to the 

 fact that they multiply so rapidly, feed so ravenously, and 

 attack practically all kinds of growing plants, including even 

 the coniferous evergreens. They are as yet comparatively 

 little injured by birds or parasitic enemies, although every 

 effort is being made by official entomologists to introduce 

 into this country the various parasites that keep the species 

 in check in Europe. 



The Fall Web-worm is a caterpillar easily found during 

 late summer and early autumn. Its unsightly nests occur 

 upon a great variety of fruit and shade trees. These Web- 

 worms hatch from eggs laid in clusters upon the leaves by 

 a whitish moth. The tiny caterpillars begin to spin a pro- 

 tective web as soon as hatched. When very young they 

 are yellowish, marked with black, and have a few hairs 

 projecting from their bodies. They spin webs over the 

 nearer leaves and then feed upon their green substance, 

 eating this out so that the network of veins is left. As the 

 days go by, they enlarge the web to cover other leaves, 

 which are in turn attacked. They molt about once a week, 

 remaining always beneath the protecting web. As they 

 become full grown, the caterpillars eat more or less of the 

 veins along with the leaf substance, but they generally avoid 

 the midribs. 



The full-grown Web-worm caterpillars are a little more 

 than an inch long, with the body densely clothed with 

 yellowish hairs. They now leave the trees and descend to 

 the ground. There they spin slight silken cocoons within 

 which they change to the chrysalis state, and remain until 

 the following June, when they emerge as moths to lay eggs 



