Bui. 111, Bureau of Entomology, U. S. Dept. of Agriculture. 



Plate II 



Fig. 1.— Wingless Progeny of Winged Hop Aphides from Alternate Host. 



(Original.) 



Fig. 2.— Willows Along Edge of Hopyard, which were Erroneously Supposed 

 to Harbor Hop Aphides. 'Original.) 



THE HOP APHIS. 



