PESTS OF THE HOP CROP. 139 



fly against the kerosened or tarred surface, and arethus 

 destroyed in large numbers. 



BEETLES FEEDING ON HOP LEAVES 



Several species of leaf beetles are frequently found 

 in the hop yards, and gnaw holes in the leaves, thus 

 disfiguring them, but seldom injuring the plant. 

 Among these, are the red-headed flea-beetle (Systena 

 frontalis), the striped flea-beetle (Phyllotreta vittata), 

 the punctured flea-beetle (Psylliodes punctulata),and the 

 twelve-spotted leaf beetle (Diabrotica 12-punctata). 

 These species were found by Dr. Smith at Waterville. 

 Mr. Pergande, at Richfield Springs, collected Phyllo- 



FIG. 71. STRIPED FLEA-BEETLE, 

 a, Larva; 6, adult. Enlarged. (From U. S. Department of Agriculture.) 



treta vittata; Crepidodcra hclxincs, the common willow 

 flea-beetle; Epitrix cucumeris, the potato flea-beetle; 

 Diabolia borealis, the common plantain leaf miner; Psyl- 

 liodes punctulata, a common and widespread species. 

 None of these insects is peculiar to the hop plant. 

 The common striped flea-beetle is shown in the accom- 

 panying figure. 



THE SO-CALLED "RED SPIDER," OR SPINNING MITE 



Hop fields in England have occasionally suffered 

 to a considerable extent from the damage done to the 



