252 Journal New York Entomological Society. tVoi. xxi. 



joint; seventh segment of 5 abdomen depressed ; auxiliary vein ending 

 close to the end of the first vein, but independently in the costa; the 

 sections of the fourth vein 1:4. 3 mm. (Hayti.*) . . .diadema n. sp. 

 Tibiffi without extensor bristles ; face less receding ; front black ; the orbits 

 broader; arista less than four times the length of the third joint; last 

 segment of 5 abdomen compressed ; auxiliary vein ending in the first 

 vein, (iiiaura Meigen.) lo- 



10. Ocellar triangle longer than wide, its sides concave; the four lower frontal 



bristles close together, the fifth (uppermost) separated by a greater 

 interval; sections of the fifth vein equal. (Proc. Ent. Soc. Wash., 



IX, 35 (1908).) (Mo., Que.,* Cal.) maura van tilice Couden. 



Not with this combination of characters 1 1- 



11. Segments of the fifth vein 1:1; segments of fourth vein 1:10; tip of 



epistome sometimes visible in profile view; orbital pubescence very 

 short, almost invisible; six frontal bristles; face carinate, its oral 

 margin nearly straight. (Eur. ; Ont., Ga.,* Pa., N. Y.,* N. J., Mass., 



l\\*) maura var. simplex Loew. 



Basal sections of fifth vein longer than the apical section ; crossveins less 

 approximated; face receding or vertical, the lower angle rounded in 

 profile ; orbital pubescence usually dense and longer 12. 



12. Face short and strongly tuberculate between the antenna, the epistome 



strongly emarginate; the lower two fronto-orbitals alone present; 

 pubescence of frontal orbits very dense. (Eur.;* Id.,* Wash.*) 



maura var. nasuta n. var. 



Face carinate, not shortened, the margin of the epistome less vaulted ; the 



upper fronto-orbitals present; orbital pubescence less dense 13. 



13. Seven fronto-orbital bristles; wings broadly rounded; segments of fourth 



vein 1 : 4. (Id.,* Wash.*) m.aura var. setifrons var. nov. 



Four frontal bristles ; segments of fourth vein 1:6 to 1:8 i4- 



14. Third vein ending near the tip of the wing, nearer the second than the 



fourth vein ; segments of fourth vein 1:6; sixth vein faint. (Eur. ;* 



Id * Wash.*) maura Meigen, sens. str. 



Third vein equidistant from the second and fourth ; the fourth vein ending 

 nearer the tip of the wing; crossveins more approximated, the seg- 

 ments of the fourth vein 1:8; sixth vein usually wanting. (Eur.;* 

 ■^^gjj *) maura var. morionella Zetterstedt. 



15. Thorax not bordered with yellow at the sides, at most a very narrow line 



present on the notopleural suture i°- 



Thorax with distinct yellow lateral borders, extending more or less broadly 

 along the notopleural suture 40- 



16. Third antennal joint black ^7- 



Third antennal joint yellow or ferruginous 34- 



1 7. Palpi black ^^• 



Palpi yellow ^^' 



18. Front, face and cheeks yellow, at most the upper orbits darkened 19. 



