6 PKOCEEDINGS OF THE NATIONAL MUSEUM vol. 68 



KEY TO NORTU AMERICAN GENERA OF MILTOGRAMINI 



1. First vein bare 2. 



First vein bristly; distal section of fifth vein more than half as long as preceding 

 section; parafacials bearing a distinct row of macrochactae, facial ridges 

 nearly parallel Opsidiopsis Townsend. 



2. Length of head at vibrissae almost equal to length at base of antennae; epistoma 



usually produced, and in profile conspicuously visible — ' 12. 



Length of head at vibrissae much less than at base of antennae; epistoma not 

 produced, at most scarcely visible in profile 3. 



3. Apical cell open at margin of wing 5. 



Apical cell closed at margin of wing 4. 



4. Distal section of fifth vein longer than preceding section; fold of fourth vein 



longer than discal cell - Taxigramma Perris. 



Distal section of fifth vein scarcely more than half as long as preceding section; 

 fold of fourth vein distinctly shorter than discal cell Hilarella Rondani. 



5. Facial ridges with bristly hairs or macrochaetae which extend not more than 



one-fourth the distance from the vibrissae to the base of the antennae 6. 



Facial ridges with strong macrochaetae which extend more than half the 

 distance from the vibrissae to base of antennae; vibrissae and ocellar bristles 

 distinctly differentiated; bristly hairs on either side of frontal vitta below 

 ocellus Sphenometopa Townsend. 



6. Parafacials with a distinct row of macrochaetae 11. 



Parafacials without macrochaetae 7. 



7. Abdomen elongate conical; macrochaetae on abdomen much larger than the 



bristlj' hairs 8. 



Abdomen subglobose; macrochaetae on abdomen scarcely differentiated 

 from the surrounding bristly hairs; head in profile with no definite angle 

 between buccal and facial margin - Oestrohilarella Townsend. 



8. Frontal rows not extending to below base of antennae and not strongly diver- 



gent below; lunule scarcely visible 9. 



Frontal rows extending to middle of second antennal joint and strongly 

 divergent below; lunule conspicuously exposed. 



Phrosinella Robineau-Desvoidy. 



9. Third vein on upper surface with but one or two small hairs near its base; arista 



thickened to near its tip Senotainia Macquart. 



Third vein on upper surface usually with a row of bristles extending at least 

 nearly halfway to the small cross vein; if not, arista not thickened beyond 

 basal half 10. 



10. Apical scutellar bristles well developed, nearly or quite as large as the extreme 



lateral scutellars; front with sides not converging anteriorly; male genitalia, 

 in repose, largely or wholly concealed within tip of abdomen. 



Gymnoprosopa Townsend. 

 Apical scutellar bristles lacking, or if present, much smaller than the other two 

 pairs of marginals; front with sides usually converging anteriorly; male 

 genitalia, in repose, extruding prominently from tip of abdomen. 



Eumacronychia Townsend. 



11. Facial ridges strongly divergent; vibrissae much less than length of second 



antennal joint above front edge of oral margin; proboscis much shorter than 



height of head .Metopia Mcigen. 



Facial ridges parallel; vibrissae at least length of second antennal joint above 

 front edge of oral margin; proboscis at least nearly as long as height of head. 



Opsidia Coquiliett. 



