Vol. 1] 



Essig. — Aphididuc of California 



345 



the abdomen. Forms large galls ou the leaf petioles, near the 

 leaves, of poplar. Campus. August 15, 1916. 



Eriosoma, sp. ? (fig. 29). An undetermined species designated 

 by the common term Wilson's bonnet gall-louse, by Patch. 



Fig. 29. Eriosoma, sp. Large pseudogall produced on the leaf of 

 English elm, Vlmus campestris Smith. Berkeley, Cal., July 8, 1916. 

 (Original.) 



Fig. 30. Eriosoma lanigera (Hausm.) Colony of the woolly apple aphis 

 on apple. (Author's illust., Ben. & Inj. Ins. Cal.) 



