KEY TO THE OKDERS 



299 



divided. Body frequently fringed with down or covered with 

 hairs, giving a bee-like appearance. Bombyliidae. 



(Bee-Flies.) 



BBB. Antennae three-jointed, with terminal appendage of di- 

 verse form and structure. Mouth forming a short, project- 

 ing horny beak; strong feet. Predaceous flies. Asilidae. 



(Kobber-Flies.) 



AAA. Antennae composed of not more than three joints and 

 an arista; 1 arista not arising from end of last segment; no 

 arched frontal suture over the antennae. (See Fig. 227, 6.) 

 ( Cyclorrhapha Aschiza. ) 

 B. Vein-like thickening between veins III and V. (See Fig. 



226. ) Syrphidae. 



(Hovar-Kieo.) 



FIG. 229. Wing venation of a Syrphicl. (After Comstock.) 



AAAA. Antenna? consisting of three joints and an arista; 

 frontal suture over antennae well marked, extending downward 

 along each side of face. (Cyclorrhapha Schizophora.) 

 B. Arista on upper side of antennae. For wing venation see 



Figure 230. Muscidae. 



(House-Fly Family.) 



FIG. 230. Wing of a Muscid. (After Comstock.) 



The suborders Orthorrhapha and Cyclorrhapha, the main sub- 

 divisions, chiefly based upon pupal characters, are omitted in 

 this scheme. Instead of a dichotomous arrangement, the prin- 

 cipal families of the order are placed under the four divisions 

 of Brauer. 



*A bristle-like appendage. 



