SMALL, ACTIVE WHITE FLIES ON FOLIAGE 



205 



and further observation will disclose the minute, slender insects that 

 are doing the mischief. They are one twenty-fifth of an inch long, 

 the larger winged individuals brownish in color and the smaller wing- 

 less forms somewhat pinkish. 



Winter is passed in debris at the base of the plants. There are 

 several generations in the course of a summer. 



Remedies are rotation of crops, or burning over infested fields in 

 winter. 



The Greenhouse White-fiy (Aleurodes vaporariorum Westw.) 

 Wherever plants are grown under glass this troublesome pest is sure 

 to put in its ai)pearance, and injure the plants by sucking their juices. 



Fig. 254. 



Larvie and adult of the Greenhouse White-fly. 

 Original. 



Enlarged. 



The adults have four wangs, covered with a whitish powder, and are 

 . active creatures, flying readily. They are about three fiftieths of an 

 inch in length. The young are flattened, oval in shape, and have 

 sucking mouth parts, like the adults. 



The insect is nearly always found on the under side of the leaves, 

 and prefers the younger foliage at the upper part of the plant. The 

 leaves attacked lose their \'itality, and if the insect is not checked, the 



