XXXVI. Family SEPSIDiE. 



Fig. 106. Piophila casei, enlarged. After Washburn. 



Head rounded; front bristly above; face perpendicular 

 or a little retreating; border of the mouth more or less 

 hairy, with or without vibrissae ; proboscis short; anten- 

 nae not porrect, usually short. Abdomen usually notice- 

 ably narrowed at the base; hypopygium prominent. 

 Auxiliary vein distinct or more or less coalescent with the 

 first vein; all the basal cells distinct. Middle tibiae with 

 spurs; tibiae usually without preapical bristle. 



The flies of this family are usually small, black and 

 elongated, with the abdomen narrowed at the base, thick- 

 ened and curved downward toward the extremity; with 

 transparent, irridescent wing, usually hyaline, but often 

 with a spot or spots toward the end, and are usually ob- 

 served about decaying vegetables, excrement, cheese, 

 ham, etc., often in swarms. The flies for the greater part, 

 run about actively and are quick in flight. The best 

 known are the species of Piophila, the larvae of which are 



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