BULLETIN 139. 



CATERPILLARS INJURING APPLE FOLIAGE IN 



LATE SUMMER. 



THE FALL WEB-WORM.* 



The coniniou Fall AVeb-worin is so named because of the 

 web which it spins over its food plant in August and Septem- 

 ber, somewhat resembling that made by the Tent Caterpillar in 

 the spring, with which it is often confused. (Concerning the 

 Tent Caterpillar see Bulletin 38 of this Station.) 



LIFE HISTORY AND DESCRIPTION. 



The motlis emerge from overwintering pupte late in June and 

 during July, frequently occurring at electric lights. The moths 

 are of a pure white color, the wings expanding an inch to an inch 

 and a quarter. This species is practically the only common moth 

 which might be mistaken for the Brown-tail Moth, which is also 

 pure white except the bushy brown tail, while the body of the 

 fall web-worm moth is white. Rarely, however, the fall web- 

 worm moths have the wings spotted more or less with black. 



Eggs. — The eggs are laid by the female during July and are 

 deposited upon the leaves of the food plants in clusters of 400 

 or 500. They are globular, about l-50th of an inch in diameter, 

 and of a pale yellowish-green color, often covered with whitish 

 do^\^a from the body of the female. They usually hatch in 

 about ten days. 



Larva. — The young caterpillars, which seem to be almost all 

 head and hair, at once commence to spin their web over the 

 fohage upon which they are feeding. Within this web the col- 

 ony from an egg mass feeds, enlarging it as it becomes neces- 

 sary. The webs are usually started at the tips of limbs and are 

 to be first noticed about August 1st. Within them the upper 



* Hyphantria texlor Harris. 



