334 



The Two-winged Flies 



hair usually light brown or whitish in color. The wings are blotched with 

 brown or blackish. Anthrax contains numerous species with short proboscis, 

 and broad flattened body covered with short hair. The wings are either 

 clear or partly colored with brown or black. In the species of the genus 

 Exoprosopa (Fig. 468) the hair of the body is very short and often in silvery 



bands across the abdomen, the pro- 

 boscis is short, and the wings usually 

 beautifully "pictured" with brown and 

 black. 



FIG. 467. FIG. 468. 



FIG. 467. A bee-fly, Bombylius major. (Twice natural size.) 

 FIG. 468. A bee-fly, Exoprosopa sp. (One and one-half times natural size.) 



In California the roads and paths, especially along streams and through 

 woods and parks, are made almost intolerable in part of the spring for driving 

 or bicycling because of hosts of small slender blackish flies 

 in swiftly dancing swarms. These are dance -flies, 

 Empididae, and their aerial dance is their mating flight. 

 I do not know that such hordes of dance-flies occur in 

 the East, but some species of 

 the family have the same danc- 

 ing habit there, and can be dis- 

 tinguished by it and by the 

 structural characters given in 

 the key. The midges, Chirono- 

 midae, also dance in swarms in 

 the air, but are readily dis- 

 tinguished from the Empidids 

 by their small fragile body, 



and long many-segmented hairy 

 FIG. 469- FIG. 470. 



FIG. 469,-Mouth-Darts of a bee-flv Bombylius sp. antennae. All the dance -flies 

 (Much enlarged.) are predaceous, sometimes 



Mtamphomyia longicauda. catching thdr prey in the aiFj 



sometimes chasing it on the 

 ground. The larvae, slender cylindrical grubs living in the soil or under leaves 



