DIOrSIDTE— SErSIDTK. Ill 



10. Cl^'pcus prominent. 17 



Clypc'us hidden 18 



17. Tlie costal vein reaches to the tliird longitudinal vein. 



BliACIIYDRUTRA LoCW. 



Tiie costal vein readies to the tip of the fourth longjitudinal vein. 



Parydra Stenhammer. 



18. Claws ahiiost straight ; pulvilli indistinct. . . Epiivdra Fallen. 

 Claws ciirved ; pulvilli distinct .19 



10. Oral border quite bare. Ilytiiea Ilalliday. 



Oral border with bristles. ........ 20 



20. Arista pubescent. Scatella Desvoidy. 



Arista pectinated. ...... C.icnia Desvoidy. 



39. DIOPSID^. 



Small species. Head prolonged into two lateral processes 

 bearing the eyes ; front bristly on the upper part only ; no 

 vibrissa on the border of the mouth. Front femora thickened. 

 Auxiliary vein much approximated to the first longitudinal 

 vein. 



But a single species of this family, Sphyracej)h.ala hrevicor- 

 nis Say, is known from North America, and it will be easily 

 enough recognized by the singular eye-stalks. The habits, 

 whether of the adult or larval stage are not known, nor are 

 they known of any other member of the family, so far as I 

 am aware. 



40. SEPSID^. 



Head rounded ; front bristly above ; face perpendicular or a 

 little retreating; border of the mouth more or less hairy, with 

 or without vibrisste; proboscis short; antennae not porrect, 

 usually short. Abdomen narrowed at the base ; hypopygiiim 

 prominent. Auxiliary vein present or absent; all the basal 

 cells distinct. Middle tibia; with spurs ; tibite usually with- 

 out preapical bristle. 



The flies belonging to tliis family arc usually small, black 



