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



Plate IX. 



Fig. 1.— Compressed-Air Spraying Machine, Showing Air Bottle, Tank, Reducing 

 Valve, and Pressure Gauge. (Original.) 



Fig. 2.— Filling Air Bottles for Compressed-Air Spraying Machine. (Original.) 

 SPRAYING AGAINST THE HOP APHIS. 



