44 DIPTEEA OP NORTH AMERICA. 



Fam. LI. DIOPSIDAE. 



Charact. — Neuration of the wings incomplete from the absence of the 

 foremost of the two small basal cells ; the auxiliary vein very much 

 approximated to the first longitudinal vein. Head prolonged in 

 two lateral apophyses bearing the eyes ; front bristly only on the 

 upper part; border of the mouth with no vibrissa?. Anterior femora 

 incrassated. 



One species, or — if the second one, described by Dr. A. Fitch, 

 should really prove different — two species of the genus Sphyrace- 

 phala Say have hitherto been found in N. A. 



Fam. LII. PIOPHILIDAE. 



Charact. — The auxiliary vein, on its whole length, is coalescent with the 

 first longitudinal vein ; with this exception the neuration of the 

 wings is complete. Front with some small bristles above only ; bor- 

 der of the mouth with a vibrissa on each side ; clypeus rudimentary; 

 legs rather stoat, almost of the structure of those of the Sciomyzidce ; 

 middle tibia? with spurs ; all the tibia? without erect bristle on the 

 exterior side before the tip. 



The three N. A. species of Piophila which I have seen are quite 

 identical with European ones; a fourth differs so much from all the 

 known Piopldlce in the form of the head and the structure of the 

 antennas, that it must be considered as the type of a new genus. 

 It seems to be the same species on which Mr. Walker has founded 

 his genus Prochyliza; if that be really so, he would, by assigning 

 it a place immediately by Ghyliza, have shown that he had been 

 fully mistaken about its true relation. 



Fam. LIIL EPHYDRINIDAE. 



Charact. — Face convex, with no distinct furrows for the reception of the 

 antenna? and without vibrissa?, though frequently beset with hairs or 

 bristles ; clypeus very much developed ; opening of the mouth large ; 

 proboscis incrassated with a swollen chin. Neuration of the wings 

 incomplete ; the auxiliary vein distinct only at its base ; the fore- 

 most of the two small basal cells reunited with the discal cell. 

 Middle tibia? with spurs. 



They are divided into three sections : Notiphilina, Hydrellina, 

 and Ephydrina. The Notiphilina are characterized by the second 



