252 Journal New York Entomological Society. [VoL xxi. 



joint; seventh segment of J 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. 

 Tibiae 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 J abdomen compressed ; auxiliary vein ending in the first 

 vein, (maiira Meigen.) 10. 



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 var. tilicc Couden. 



Not with this combination of characters 11. 



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., 



111.*) 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 antennae, 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 I : 4. (Id.,* Wash.*) m,aura var. setifrons var. nov. 



Four frontal bristles ; segments of fourth vein 1:6 to 1:8 14. 



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.;* 

 Wash.*) maura var. morionella Zetterstedt. 



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



present on the notopleural suture 16. 



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

 along the notopleural suture 40. 



16. Third antennal joint black 17. 



Third antennal joint yellow or ferruginous 34. 



1 7. Palpi black i8. 



Palpi yellow 33. 



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



