136 a. H. TYLER TOWXSHND. 



32. Two rows of frontal bristles, do orbital bristles. 



Sarcomacroiiyoliia Twus. 

 <^nly one row of frontal bristles, orbital bristles present. 



Euiiiacronycliia Twus. 



33 Sides of face bare; arista often bent; third antennal joint nearly round, 

 seed-like Tri.'Ka. 



Sides of face hairy 34. 



:}4. Vibrissse inserted nearly on oral niarjjin 35. 



V'ibrissEe inserted considerably above oral margin 3(). 



35. Bristles on sides of face consisting of a well defined row; arista abruptly 



thickened on ba.sal half L.ac«0|»rosO|)a Twns. 



Bristles ou sides of face consisting only of several below near eye margin; 

 arista thickened at base, pnbesceut Sarcotachinella Twns. 



36. Front of % about one-third width of head; both sexes witii orliital bristles. 



MacronycUia Edi. 

 Frontof % one-fifth to one-sixth width of head ; % ; without orbital bristles. 



Trixoclii^ta Twns. 



.37. Vibrissse inserted on, or slightly above oral margin; abdomen oval 38. 



Vil)rissiE inserted at some distance above oral margin .39. 



38. Second aristal joint elongate Ha^ocha'ta Twns. 



Second aristal joint not elongate Masicera Mcq. 



39. Abdomen conical "lO. 



Abdomen oval.... ; Brachyconia Rdi. 



40. Antennae nearly or quite as long as face ; if not quite so long, then the second 



joint elongate ; face extended far below eyes.... ...Meigenia R. D. 



Autennse hardly nioi'e than half length of face, first two joints short. 



Senotainia Mcq. 



41. Proboscis elongate, slender, labella more or less distinct .4|>liria R. D. 



Proboscis short, fleshy 42. 



42. Second antennal jointnot elongate, not more than one-half length of third. .43. 

 Second antennal joint elongate, only a little shorter than third ; apical cell 



petiolate Hesperomyia B. & B. 



43. Front rather strongly horizontally projecting, the face very receding 44. 



Front not horizontally projecting 46. 



44. Third antennal joint much developed, ten times length of second, stont. 



Hypertropliocera Twns. 

 Third joint very much smaller and shorter, apparently compressed 45. 



45. Apical cell short petiolate; facial ridges nearly parallel, facial depression 



narrow; antennae about one-half length of face, third joint peg-like at 



apex Eiitliyprosopa Twns. 



Apical cell closed in border; facial ridges more curved, third antennal joint 

 longer, not peg-like at apex Neotractocera Twns. 



46. Vibrissje inserted on oral margin, facial ridges absolutely bare. 



Oyuiiioprosopa Twns. 



Vibrissse inserted a good distance above oral margin, facial ridges more or 



less bristly on lower half Pseudatractocera Twns. 



47. Apical cell closed 48. 



Apical cell open 49. 



