430 ECONOMIC ZOOLOGY AND ENTOMOLOGY 



They have similar habits also, except that the adult of the 

 spring canker-worm lays her eggs early in the spring, while the 

 moth of the fall canker-worm lays hers late in the fall. The 

 larvae of both species issue about the same time in the spring 

 and feed on the tender foliage. The young canker-worms 

 have a habit of dropping from the tree when it is jarred or 

 shaken and hanging suspended by a slender thread which they 



FIG. 203. California tussock-moth, Hemerocampa vetusta; larva and co- 

 coon with an egg mass on the cocoon. (About natural size.) 



spin from the mouth as they drop. They pupate in the ground 

 and the spring canker-worm passes the winter in this stage, 

 the adult issuing early in the spring. The female moth is 

 entirely wingless and less than one-half of an inch long. They 

 climb up the trunks of the trees and lay their eggs in irregular 

 masses underneath the loose bark or in cracks or crevices. The 



