20 PEOCEEDIXGS OF THE iSTATIOXAL MUSEUM. vol.63 



3. Hind femur of male with manj' black setulae ventrally ; thorax with three 



pairs of dorsocentral bristles; arista Ions haired; hind femur without 



preapieal anteroventral bristle notata Fallen [European only]. 



Hind femur of male without black setulae ventrally ; arista short haired- i 



4. Hind femur without an auteroventral bristle near apex ; thorax with four 



pairs of dorsocentrals occidentalis Malloch. 



Hind femur without an anteroventral bristle near apex ; thorax with three 



pairs of dorsocentrals ; arista very short haired, 



deceptor Malloch, new sijecies. 

 Hind femur with a rather strong outstanding anteroventral bristle near 



apex ; thorax with three pairs of dorsocentrals 5 



5. Eighth alxlominal tergite with a backwardly directed spine at apex of the 



downwardly directed lateral extension on its posterior angle ; hypopygium 



as Figures 18, 20, and 21 fraterna Loew. 



Eighth abdominal tergite with a slightly curved downwardly directed spine 

 at apex of the lateral process on its anterior angle ; hypopygium as la 

 Figures 24 and 26 pernotata Malloch. 



6. Second, and sometimes part of basal or third segment of hind tarsus black- 



ened, in male the blackened parts generally dilated ' 



Hind tarsi pale, the segments in male not dilated 11 



7. Two segments of hind tarsus in male and female partly blackened; in males 



with a pair of long, apically dilated hairs at apex of the three basal seg- 

 ments 8 



Only one segment of hind tarsus blackened ; no such hairs on tarsus of 

 males 9 



8. Second and third segments of hind tarsus in both sexes partly blackened, 



in male broadly dilated; almost all of marginal and submarginal cells of 



wings blackened ornatipes Johnson. 



Apices of basal and second segments of hind tarsus in both sexes blackened, 

 the second in male broadly dilated ; fuscous mark on costal margin of 

 wings sometimes broadly interrupted along costa between cross-veins and 

 again, narrowly, between apices of second and third veins, 



melanderi Johnson. 



9. Costal margin of wing suffused from apex of auxiliary vein to apex of 



fourth, less distinctly so between cross-veins ; second segment of hind 

 tarsus distinctly but not greatly dilated in male; hind tibia without long 



fine hairs apically on posterior surface houghi Coquillett. 



Costal margin of wing not suffused proximad of a vertical line drawn 

 from outer cross-vein 10 



10. The spots at apex of second vein and on middle of ultimate section of third 



almost directly above outer cross-vein, sometimes connected with it; 

 second segment of hind tarsus of male broader than long; hind tibia of 

 male with some long fine hairs on postero-ventral and posterior surfaces 



apically compedita Loew. 



The spots above referred to distinctly distad of the one on outer cross-vein 

 and not connected with it ; second segment of hind tarsus of male distinctly 

 longer than wide ; hind tibia of male without long fine hairs apically, 



disjuncta Johnson (similata Malloch). 



11. The entire costal margin of wings broadly brown including the costal and 



subcostal cells sheldoni Coquillett. 



Costal margin of wing largely hyaline, clouded only from a little before apex 

 of second vein 12 



12. Thorax with 4 pairs of strong dorsocentral bristles 13 



Thorax with 8 pairs of strong dorsocentral bristles 14 



