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