180 CONNECTICUT GEOL. AND NAT. HIST. SURVEY [BuU. 



56. Ocellar triangle large; fifth vein witli a distinct curvature near the 



middle of the discal cell CHLOROPIDAE 



Ocellar triangle small; fifth vein straight or without a sharp curvature. 



DROSOPHILIDAE 



57. Costa broken at the humeral crossvein 58 



Costa not broken at the humeral crossvein 60 



58. Postocellars divergent AGROMYZIDAE 



Postocellars convergent, parallel or absent 59 



59. A pair of convergent frontal bristles anteriorly; inter f rentals often 



present PHYLLOMYZIDAE 



Anterior f rentals not convergent DROSOPHILIDAE 



60. Postocellar bristles convergent OPOMYZIDAE 



Postocellar bristles divergent or absent 61 



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



front CANACEIDAE 



Ocellar triangle short 62 



62. Costa fractured or weakened at the apex of the auxiliary vein 63 



Costa not at all weakened PERISCELLIDAE 



63. Oral vibrissae present AGROMYZIDAE 



Oral vibrissae absent 64 



64. Sternopleural bristle present OPOMYZIDAE 



Sternopleural bristle absent PSILIDAE 



65. Oral vibrissae present 66 



Oral vibrissae absent 72 



66. Mesonotum and scutellum convex, if i-ather flattened the abdomen and 



legs not bristly 67 



Mesonotum and scutellum flattened; legs and abdomen conspicuously 

 bristly COELOPIDAE 



67. Postvertical bristles divergent 69 



Postvertical bristles convergent 68 



68. Orbital plates bearing ihe frontal bristles short and oblique. 



HELOMYZIDAE 

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

 almost so CHYROMYIDAE 



69. Second basal and discal cells separated 70 



Second basal and discal cells confluent DROSOPHILIDAE 



70. Anterior half of the front with strong bristles, two to four pairs pres- 



ent on the front; third antenual segment short and rather orbicular, 



the arista subapical CLUSIIDAE 



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

 terior half; arista sub-basal , 71 



71. Eyes round; occiput convex and prominent PIOPHILIDAE 



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



LONCHAEIDAE 



72. Legs long and slender, stilt-like; apical cell narrowed 73 



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

 ly narrowed 76 



73. Propleura haired 74 



Propleura bare in the middle 75 



74. Pteropleura haired on whole surface TANYPEZIDAE 



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



c^iscal MICROPEZIDAE 



75. Arista apical NERIIDAE 



Arista dorsal CALOBATIDAE 



76. Apical cell closed or almost so in the wing margin; abdomen cylindri- 



cal, the genitalia usually large CONOPIDAE 



Apical cell not strongly narrowed or the abdomen short and broad 77 



77. Some or all of the tibiae with preapical dorsal bristle 78 



Tibiae without preapical bristle 81 



