58 THE MONTHLY BULLETIN. 



the fall all of the adult forms leave the galls and either hibernate in 

 the adult or egg form. The life history has not been fully worked out. 



Distribution. — Throughout the State, wherever the host plants 

 grow. 



Food Plants.— The common cottonwood {Populus trichocarpa) , Fopu- 

 lus fremontii, P. halsamifera var. angustifolia. 



SOLANUM ROOT LOUSE. 



Trifidaphis radicicola (Essig). 



General Appearance.— The apterous females are distinctly globular 

 in shape and vary from amber to cream-color and often with a fine, 

 white, powdery covering. The winged forms are amber with head and 

 thorax dark. The wings are also dusky. Length, 1 to 2 mm. 



Life History. — The lice are subterranean in their habits and are 

 evident during the early spring and the entire summer. The winged 

 forms appear in July and August. It has not been determined whether 

 eggs are deposited or not, but so far the writer has been unable to find 

 any. 



Distribution. — Throughout the central and southern parts of the 

 State; especially abundant in the south. 



Food Plants. — Roots of Solannm douglasii, Amaranthus retroflexus 

 and potato tubers. 



MONTEREY PINE LOUSE. 



Essigella caUfornica* (Essig). 

 (Pig. 47.) 



General Appearance. — Very slender; light green; covered with 

 minute red dots ; slightly pruinose ; and with noticeably long hind legs. 

 Length 1.6 to 2 mm. 



Life History. — So far as known all stages are passed on the pine 

 trees where they are not abundant until the summer, although specimens 

 were taken in the winter. Two forms, apterous and winged females, are 

 present. 



Distribution. — Throughout the State. 



Food Plant. — Monterey pine (Pinus radiata). The insect works on 

 the needles around which it clasps its long hind legs for support. 



Natural Enemies. — Internal parasites and predators hold this species 

 in check so that it does little or no damage. 



''The specific name has been changed to agree with tlie new generic name. 



