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 



FIG. 186. A robber-fly (Erax sp.); 3 times natural size (after Williston). 



187 



188 



FIG. 187. Robber-fly (Pro- 

 machus vertebratus Say); natural 

 size (after Washburn from Willis- 

 ton). 



FIG. 1 88. A bee-fly (Exoprosopa 

 sp.); 1 1 times natural size (from 

 Williston after Kellogg). 



which attract the Coccinellidae, and the syrphus flies, 

 eaten by many birds. 



Cherries are 



