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 débris 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-fly (Alewrodes vaporariorum Westw.) 
Wherever plants are grown under glass this troublesome pest is sure 
to put in its appearance, and injure the plants by sucking their juices. 
Fig. 254.— Larvee and adult of the Greenhouse White-fly. Enlarged. 
Original. 
The adults have four wings, covered with a whitish powder, and are 
active creatures, flying readily. They are about three fiftieths of an 
inch in length. The voung 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 vitality, and if the insect is not checked, the 
