MAINE AGRICULTURAL EXPERIMENT STATION. 47 



c. CATERPILLARS LIVING IN WEB NESTS WHILE 

 THE TREE IS IN LEAF, OR MORE OR LESS 

 CONCEALED IN FOLDED LEAF OR BUD. 



Fall Web Worm. 

 (Hyphantria cunea.) 



Fig. 19. (After Riley). Fig. 20. (After Howard). 



The mature insect is a moth with a wing expanse of about 

 1 -J inches. It varies much in coloration but the most common 

 form is white or slightly fulvous with white wings. The wings 

 may be pure white or dotted with black and brown. In the 

 spring the moths emerge from the cocoons in which they have 

 passed the winter and the female deposits eggs upon a leaf in 

 May or June. Each moth lays about 400 eggs from which 

 hatch minute caterpillars in 10 days or more according to 

 weather conditions. These caterpillars remain together and 

 cover themselves with a small silken web. As they grow, more 

 and more leaves are drawn into the web which may in time 

 include the leaves of several small branches or all upon a large 

 branch. Such webs sometimes attain dimensions of several 

 feet and are conspicuous and unsightly masses. 



If they are so numerous on one tree that the food supply 

 gives out they leave the web and seek other trees. Otherwise 

 they remain until they are full grown (a little more than an 

 inch in length), when they drop to the ground and seek a place 

 where they may make cocoons. Recesses which attract them 

 for this purpose are crevices in bark, spaces under boards or 

 door steps, or near the surface of the ground in rubbish. These 

 insects pupate within thin, almost transparent cocoons and 

 remain in them all winter, emerging as mature moths in the 

 spring. 



