I^EW YoEK Agkicultukal Expeeiment Station. 411 



that often occur in sufficient numbers to do serious injury. 

 These are the spring canker worm {Paleacrita vernata Peck) and 

 the fall canker worm (Anisopteryx pometaria Harr.) The former 

 is the more common and injurious of the two. The life histories 

 of the two species are very similar except that the eggs of the 

 spring canker worm are laid in the spring and those of the fall 

 canker worm in the fall. The eggs of both species hatch in the 

 spring about the time the leaf buds are unfolding. 



Descriptions. — The eggs of the former species are placed some- 

 what promiscuously in sheltered places on the twigs. They are 

 small oval eggs and the shell has a brilliant pearly luster. The 

 eggs of the latter species are placed on end side by side in quite 

 regular masses. They are somewhat cylindrical but smaller at the 

 base and flattened at each end. 



When first hatched the caterpillars of both species are very 

 email and of a light green color. They devour the leaves rapidly. 

 When disturbed they will drop, suspending themselves by silken 

 threads. When mature they are about an inch long and vary in 

 color from light green to darker shades. When ready to pupate 

 they go into the ground, where the cocoon is spun and the chrysalis 

 formed. Most of the spring canker worms remain in the ground 

 until the first warm days of the following spring, but those of the 

 other species come out of the ground in the fall. The adults of 

 both species are moths. The females are wingless and the males 

 winged. 



Treatment. — There are two principal methods of combating 

 these insects. First the females may be trapped while endeavor- 

 ing to ascend the trunk of the tree. ITumerous traps have been 

 tested including bands of tin, cloth, waste wool, tarred paper and 

 certain chemical preparations. Several patent metal devices for 

 trapping the moths have been put upon the market recently. 

 The most important point in connection with the use of traps in 

 general is to put them on early in the season. It is usually advis- 

 able to put the metal traps in place early in the fall to catch the 



