OF WASHINGTON. 261 



24. Femora of front legs thickened, those of middle legs spinose on the 



under side 26 



Femora not thickened, those of middle legs not spinose 25 



2v Anal cell only reaching middle of the second basal cell, 



Symballophthalmus Beck. 

 Anai cell nearly reaching apex of the second basal... Platytelma Rond. 



26. Sixth vein present, sometimes indistinct 27 



Sixth vein wholly wanting, second basal cell longer than the first, 



third joint of antennae short-oval Tachypeza Meig. 



27. Last antennal joint oval, shorter than the w\\$>\.&...Pl(itypalpus Macq. 

 Last joint elongated, longer than the artista Phoroxypha Rond. 



28. Front femora thickened, axillary angle of wings not projecting, 



Chelipvda Macq. 

 Front femora slender, axillary angle of wings strongly projecting, 



Bicellaria Macq. 



29. Antennal arista apical 31 



Antennal arista dorsal or subapical 30 



30. Palpi narrow, as long as the proboscis, second vein near its apex bent 



forward at nearly a right angle Phoneutisca Loew. 



Palpi broad, front of an equal width Sttlpon Loew. 



31. First pair of femora thickened 32 



First pair of femora not thickened 33 



32. Eyes contiguous or nearly so below the antennae, hind tibiae bearing 



at most two or three bristles Tachydromia Meig. 



Eyes widely separated below the antennae, hind tibiae bearing many 

 bristles Coloboneura Mel. 



33. Third joint of antennae short-oval 34 



Third joint elongated Elaphropeza Macq. 



34. Second basal cell equal to or shorter than the first, 



Chersodromia Walk. 

 Second basal cell longer than the first Drapetis Meig. 



35. Anal cell present 36 



Anal cell wholly united with the axillary, discal cell united with one 



of the others, fourth vein forked Hemerodromia Meig. 



36 Second posteria cell long-petiolate 62 



Second cell sessile or nearly so 37 



37. Discal cell separated from the second basal 38 



Discal cell united to the second basal Neoplasta Coq. 



38. Arista much longer than the third antennal joint , 39 



Arista at most as long as the third antennal joint, the latter usually 



elongated .. 55 



39. Axillary angle strongly projecting 52 



Axillary angle not or only slightly projecting 40 



40. Last joint of antennae short-oval, proboscis shorter than height of 



head , 41 



Last joint narrow and greatly elongated, proboscis as long as height 

 of head, directed downward Trichopeza Rond. 



