1!U 



INJURIOUS W'l> BENEFICIAL [NSECTS OF CALIFORNIA. 



ALEYRODID/E (Family) 



MEALY WINGS OR WHITE FLIES 



This family is composed of very small insects closely allied to the 

 coccids and plant lice. The beak seems to he inserted between the fore- 

 legs; the feet are two-segmented; the antennae, when present, are seven- 

 articled in adults. There are four opaque, white wings which are pres- 

 ent in the mature males and females and are held flat over the body 

 when at rest. The Larvae and nymphs are flat and greatly resemble 

 scale insects. They are usually found only upon the foliage, the under 

 sides of the leaves being favorite feeding places. 



The distribution of the ordinary and non-destructive members of 

 this family is wide throughout the State, but the citrus infesting white 

 fly is exceedingly limited and every possible means are being exercised 

 by the State Commission of Horticulture to completely eradicate Dia- 

 leurodes citri (R. <fc 11.), the only species now present. 



The control of the white flies is the .same as recommended for scale 

 insects and consists of spraying and fumigation. 



Ladybird beetles and hymenopterous parasites prey quite extensively 

 upon these insects. 



THE CITRUS WHITE FLY 



Diuleurodes citri (Riley and Howard) 

 (Alcyrodes citri Riley and Howard) 



(Figs. 171. 172) 



Description. — The adult white flies are about T ] ]7 inch long and have 

 yellow bodies and opaque wings covered with a hue white powder. The 

 males have a characteristic tuft on 

 the under side of the abdomen. The 

 pale yellowish-green eggs are sus- 

 pended on short stalks. The first 

 hatched young have Legs and an- 

 tenna' like a small scale insect, but 

 after molting these disappear and 

 the body becomes flat, greatly resem- 

 bling ;i soft scale. The development 

 of the insect takes place under the 

 flattened scale, which gradually be- 

 comes raised, showing segmentation 

 and yellowish color. The adults 

 emerge by breaking through the top 

 of the skin. 



Life History. - The w i n t e r is 



passed in the mature larval stage, 



usually on the under sides of tin 1 



leaves. Early in the spring the 



pupae appear and in March and 



April the adults emerge. The eggs 



are deposited upon Hie Foliage* the 



larvae beginning to hatch in about 



three weeks. The first hatched young have legs and other appendages, 



much ms do young scale insects. They soon settle to feed and after a 



Fig. 171. — The citrus white fly, Dia- 

 leurodes citri < R. & II.). Adults en- 

 l.i rged six times, i < (riginal ) 



