12 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.63. 



13. Bucca one-sixth the eye height 14 



Bucca one-twelfth the eye height ; third antennal joint of the female at 



least three times the length of the second ; the two uppermost frontal 

 bristles strong and reclinate; thorax and abdomen black, gray pol- 

 linose formosa, new species. 



14. Male with dense patches of fine hair on the hind tergite of the abdomen 



near the middle below ; female with depressed hairs on the tlilrd terg- 

 ite above eudryae Townsend. 



Male without such patches of hair, female with erect hairs on the mid- 

 dle of the third abdominal segment (if with linear bucca and swollen 

 palpi, see inflatipalpis) valens, new species. 



15. Palpi yellow 21 



Palpi black 16 



16. Mid tibiae with two or more bristles on the outer front side near the 



middle 17 



Mid tibiae with one bristle on the outer front side near the middle 

 (nigripalpis Townsend preoccupied) caesar Aldrich. 



17. Costal spine short, scarcely distinguishable from the adjacent bristles— 18 

 Costal spine long ; abdomen black, subshining ; bucca one-third the eye- 

 height; three dorsocentral macrochaetae trisetosa Coquillett. 



18. With three sternopleural bristles; usually four dorsocentral macro- 



chaetae present 19 



With four sternopleural bristles ; eyes thinly hairy ; front of male very 

 narrow, 0.147 the head width submissa, new species. 



19. Scutellum yellowish 20 



Scutellum black ; front at vertex in both sexes less than eye width 



(nigripalpis Townsend preoccupied) caesar Aldrich. 



20. Front at vertex about two-fifths the head width ; silvery poUinose, some- 



what blackish at vertex ; penultimate joint of the arista usually twice 



as long as broad vulgaris Fallen. 



Front at vertex much narrower ; golden pollinose, the penultimate joint 

 of the arista short crassiseta, new species. 



21. Mid tibiae with two or more bristles on the outer front side near 



the middle ^ 29 



Mid tibiae with but one bristle on the outer front side near the 



middle 22 



22. Head, thorax, and abdomen yellow pollinose 26 



Head, thorax, and abodmen black, gray pollinose 24 



23. Omitted. 



24. Abdominal hairs depressed; bucca one-eighth or .less the eye height 25 



Abdominal hairs erect ; bucca one-fifth the eye height fronto Coquillett. 



25. With two sternopleural bristles (rarely a weak third sternopleural 



bristle present) blanda Osten Sacken. 



With three stout sternopleural bristles; apical scutellar bristles di- 

 rected backward blandita Coquillett. 



26. With three dorsocentral macrochaetae and two or three sternopleural 



ones 28 



With four dorsocentral macrochaetae and three sternopleural ones; 

 bucca one-fifth the eye height 27 



