ART. 11. FLIES OF THE FAMILY CLUSIIDAE MELANDER AND ARGO. 35 



12. Tibiae, tarsi, scutellum and face yellow; wings bifasciate. (Panama) 



fascipennis, new species. 



Tibiae, front tarsi, scutellum and face black; outer two-thirds of wings dark. 



(Costa Rica) annulata, new species. 



13. Lateral black marks of mesonotum extending over the humeri 14 



Humeri yellow like the central anterior portion of the notum; hypopygium yel- 

 low 17 



14. Posterior half of mesonotum and the scutellum black, abdomen black; tibiae dark; 



prescutellars absent; wings infumated except at base 15 



Middle vitta of notum, metapleurae, scutellum and abdomen including hypopy- 

 gium black; legs wholly yellow; prescutellars absent; wings uniformly yellow- 

 ish; base of arista densely plumose (Costa Rica) plumatella, new species. 



Mesonotum and scutellum yellow except for lateral stripes, abdomen mostly 

 yellowish; tibiae yellow; prescutellar setae present; wings darkened along costa 

 and tip. (Eastern U. S.) (if lateral stripe is bisected and marginal cell not 



dark see bivittata.) latifrons Loew. 



lb. Notum with black center stripe; second vein distinctly diverging from third 



near tip 16 



Notum uniformly black except for a central round yellow spot toward the front; 

 second vein slightly diverging from thfrd. (Costa Rica) 



xanthomelana, new species. 



16. Wings broad, twice as long as wide, costa strongly arched opposite posterior crose- 



vein and spinulose, the second vein abbre\dated, costal sections 2.5:2:1, sec- 

 tions of fourth vein 1 :2. (Costa Rica) latipennis, new species. 



Wings normal, more than twice as long as wide, second vein not shortened, the 

 costal sections 4.5:1.5:1, sections of fourth vein 1:2.5. (Costa Rica) 



liturata, new species. 



17. Posterior portion of mesonotum black, apparently marked with three fused vittae 



which disappear in front, Bcutelliim and metathorax black; only front tarei 

 brown. (Peru; Costa Rica) (if notum has broad black stripe tapering anteriorly 

 and extending laterally as bowed brown band, see pictipennis Kertesz.) 



dorsata Czemy. 

 Mesonotum bivittate 18 



18. Wings with apical clouding; front tibiae and tarsi more or less brown; prescutellars 



present 19 



Wings uniformly hyaline; legs yellow; no prescutellars; scutellum brown 20 



19. Lateral mark of thorax obliquely interrupted by the suture, the anterior spot 



adjacent to the margin (sometimes absent), the posterior located between the 

 supra-alar and dorsocentral bristles; scutellum laterally or wholly black. (Costa 



Rica) bivittata, new species. 



Lateral mark of thorax not extending in front of suture; scutellum black or yellow 



bistrigata Kertesz. 



20. Yellow of sides of mesonotum extending behind suture. (West Ind.; C. 



Amer.) lumbalis Williston. 



I>ateral black marks of mesonotum extending in front of suture. (West Ind.) 



valida Williston. 



21. Femora devoid of flexor combs of setae; a faint cloud at end of second vein; front 



tarsi alone somewhat dusky; body entfrely yellow. (U. S.).flava, new species. 



Underside of anterior femora furnished with a row of black or sometimes pale 



setae 22 



22. Mesosternum with long hairs; abdomen bristly with hairs; hypopygium longer 



than depth of abdomen; cheeks silvery pruinose when viewed from above. .23 

 Mesosternum short-hairy but not setose; abdomen not markedly bristly; hypopy- 

 gium small 24 



