XLIX. Family HETERONEURID^. 



Head broad, subhemispherieal. Face short, nearly 

 vertical; vibrissas present. Front broad, bristly to or 

 nearly to the root of the antennae. Ocellar bristles usu- 

 ally present; postvertical bristles divergent. Antennae 

 porrect; first two joints short, the third usually rounded; 

 arista bare, pubescent or short plumose. Proboscis short; 

 palpi rather broad. Body more or less elongate. Legs 

 rather long and slender; tibiae with or without a preapi- 

 cal bristle. Venation complete; basal cells small; first 

 longitudinal vein short, the auxiliary narrowly sepa- 

 rated from it; sixth vein not reaching the wing margin. 



The members of this small family of rather small flies 

 are to be found throughout the summer in shady places 

 by the sides of brooks, or in the forests about the trunks 

 of decaying trees; in damp meadowy places among the 

 grass; on leaves, etc. 



Larvae of this family have been found in decaying wood, 

 under bark of trees, etc. They are slender, cylindrical, 

 slightly thickened posteriorly, white in color. The mouth 

 booklets are very small, the body segments not distinctly 

 separated; abdominal segments with a transverse swell- 

 ing for locomotion. The larvae have the power of leap- 

 ing as have those of Piophila. The act is performed by 

 fixing the mouth booklets in the two chitinous, straight 

 or curved booklets on the upper side of the last segment 

 and then suddenly releasing them. The puparia are 

 yellowish, ellipsoidal and with two horns on the last 

 segment as in the larvae. 



Mr. Czerny has attempted recently to break up the 

 genus Heteroneura, using for generic characters the bris- 

 tles of the front chiefly. I gravely doubt whether all 



3i8 



