254 



NORTH AMERICAN DIPTERA 



Syrnhidse IV. — 54, Criorrhina caudata; 55, Brachjopa basilaris, head from in front; 56, 

 Brachyopa basilaris; 57, Brachyopa nigricauda; 58, Clialcosyrphus depressus ; 59, Microdon 

 fulgens; 60, Cynorhina nigripes; 61, Clialcosyrphus depressus; 62, Chalcomyia aerea ; 63, 

 Cynorhina metcalfi ; 64, Cynorhina pictipcs. 



