224 DRY AND MESOPHYTIC FOREST COMMUNITIES 
by pollen-gathering insects (Andrenidae, Apidae, syrphus flies, etc.). 
The kingbirds feed on these insects; one article of their diet, the robber- 
flies, is always common. A chrysomelid beetle (Disonycha quinquevittata) 
commonly feeds upon the willow. The cherry is attacked by aphids 
Fic. 186.—A robber-fly (Erax sp.); 3 times natural size (after Williston). 
188 
Fic. 187.—Robber-fly (Pro- 
machus vertebratus Say); natural 
size (after Washburn from Willis- 
ton). 
Fic. 188.—A bee-fly (Exo proso pa 
sp.); 13 times natural size (from 
187 Williston after Kellogg). 
which attract the Coccinellidae, and the syrphus flies. Cherries are 
eaten by many birds. 
