tablp: of families 25 



59. Ocellar triangle large and shining, reaching the anterior edge of the 



front (p. 356) CANACEID^ 



Ocellar triangle short 60 



60. Second vein joining the costa just beyond the apex of the first. 



(p. 328) ASTEIID.^ 

 Second vein joining the costa far beyond the apex of the first 61 



61. Custa fractured or weakened at the apex of the auxiliary vein 62 



Costa not at all weakened (p. 323) PERISCELLID^ 



62. Oral vibrissse present (p. 332) AGR0MYZID7E 



Oral vibrissge absent 63 



63. Sternopleural bristle present (p. 329) OPOMYZID^ 



Sternopleural bristle absent (p. 374) PSILID^ 



64. Oral vibrissse present 65 



Oral vibrissse absent 71 



65. Mesonotum and scutellum convex, if rather flattened the abdomen and 



legs not bristly 68 



Mesonotum and scutellum flattened; legs and abdomen conspicuously 

 bristly (p. 376) CCELOPID^ 



66. Postvertical bristles divergent 68 



Postvertical bristles convergent 67 



67. Orbital plates bearing the frontal bristles short and obliciue. 



(p. 378) HELOMYZID^ 

 Orbital plates long, extending to the anterior margin of the front or 

 almost so ^ (p. 371) CHYROMYID.^ 



68. Second basal and discal cells separated 69 



Second basal and discal cells confluent (p. 325) DROSOPHILID^ 



69. Anterior half of the front with strong bristles, two to four pairs present 



on the front; third antennal segment short and rather orbicular, the 



arista subapical T (p. 362) CLUSIID^ 



At most two pairs of rather weak frontal bristles situated on the pos- 

 terior half; arista sub -basal 70 



70. Eyes round; occiput convex and prominent (p. 310) PIOPHILIDi33 



Eyes, vertical, elongate; occiput concave; antennae long. 



(p. 298) LONCH^ID^ 



71. Legs long and slender, stilt-like; apical cell narrowed 72 



Legs shorter and more robust, if rather long the apical cell not strongly 



narrowed 75 



72. Propleura haired 73 



Propleura bare in the middle 74 



73. Pteropleura haired on whole surface (p. 301) TANYPEZID^ 



Pteropleura bare on anterior half; second basal cell confluent witli the 



discal (p. 306) MICROPEZID^ 



74. Arista apical (p. 308) NERIID^ 



Arista dorsal (p. 303) CALOBATID^ 



75. Apical cell closed or almost so in the wing margin; abdomen cylindrical, 



the genitalia usually large (p. 265) CONOPID^ 



Apical cell not strongly narrowed or the abdomen short and broad 76 



