344 



University of California Publications [Entomology 



Fig. 27. Fempliigus popuUtransvcrsus Riley. Galls formed on the leaf 

 petioles of poplar. Berkeley, Cal., Aug. 17, 1916. (Original.) 



^ 



Fig. 28. Pemphigus popuUtnuisrersufi Riley. Stem-mother or funda- 

 trix, and virgogeniae. Campus, Aug. 17, 1916. (Original.) 



