296 Hominoocious Arthropods 



h. Arista terminal; hind metatarsus enlarged, sometimes orna- 

 mented, hind tarsus more or less flattened beneath 



PLATYPEZID^E 



hh. Flies having a different combination of characters. 



i. Head large, eyes occupying nearly the entire head; cell 

 R 4 + s narrowed in the margin; small flies . .PIPUNCULID/E 

 ii. Head and eyes not unusually large. 



j. Squamae (tegulas, or calyptrae, or alulae) not large, often 

 quite small, the lower one lacking, or at most barely 

 projecting from below the upper one (antisquama) ; 

 front of both male and female broad, the eyes therefore 

 widely separated; posthumeral and intraalar macro- 

 chaeta not simultaneously present; thorax usually 

 without a complete transverse suture; postalar callus 

 usually absent; the connectiva adjoining the ventral 

 sclerites always visible; hypopleural macrochaetae 

 absent; last section of R4+5 and Mi+2 with but few 

 exceptions nearly parallel; subcostal vein often wanting 

 or vestigial or closely approximated to RI; the latter 

 often short, basal cells small, the posterior ones often 

 indistinct or wanting; vibrissae present or absent 



ACALYPTRATE MUSCOIDEA 



k. Subcosta present, distinctly separated from RI at the 

 tip; RI usually ends distad of the middle of the 

 wing; the small basal cells of the wing distinct. 



I. A bristle (vibrissa) on each side of the face near the 



margin of the mouth. CORDYLURID^E, SEPSIDJE, 

 PHYCODROMID^E, HETERONEURID/E, HELOMYZID.E. 



II. No vibrissae present. 



m. Head nearly spherical, cheeks broad and re- 

 treating; proboscis short; the cell RS closed or 

 narrowed in the margin; legs very long; tarsi 

 shorter than the tibiae. Calobata and other 



genera MlCROPEZlD JE 



mm. Flies with another combination of characters. 

 RHOPALOMERID^;, TRYPETID^E, ORTALID^E, 

 SCIOMYZID^E. 



kk. Subcosta absent or vestigial, or if present, then 

 apparently ending in the costa at the point where 

 RI joins it; RI usually ends in the costa at or before 

 the middle of the wing. 



I. Arista long plumose, or pectinate above; oral vibris- 



sae present; anal cell complete; costa broken at 

 the apex of RI. Drosophila, Phortica, and other 

 genera DROSOPHILID^: 



II. With another combination of characters. 



m. The cell M and first M2 not separated by a cross- 

 vein; anal cell absent; front bare or only 



