4 PROCEEDINGS OF THE NATIONALi MUSEUM. vol. 65 



8. Orbit with several long fine hairs above the bristle ; cheeks, frons, and meso- 



notum with rather dense erect black hairs ; wings whitish or yellowish, iu- 

 fuscated at bases ; scutellum with some long erect hairs on disk near apex 

 as well as on the margins; pteropleura usually with one or two long hairs 



in center hirta Malloch. 



Orbits bare or with a single hair above bristle; cheeks, frons, and mesono- 

 tum with more sparse black hairs ; scutellum generally bare on disk ; 

 pteropleura bare affinis Malloch. 



9. Third antennal segment but little longer than wide; scutellum with four 



strong bristles and no fine hairs ; face of male silvery ; ovipositor of fe- 

 male nearly as broad as frons, acutely pointed at apex, the preapical hairs 

 very short ; auxiliary vein nearly fused with first at apex. 



arkansensis >[alloch 



Third antennal segment about three times as long as wide; scutellum with 



some fine hairs on margins as well as the four long bristles ; face of male 



not silvery ; female ovipositor slender, very much narrower than f rons_ 10 



10. Glossy upper portion of orbits black; orbital bristle not proximad of ante- 



rior ocellus; cheek with dense short stiff hairs; third antennal segment 

 not over three times as long as wide, almost entirely orange red. 



ruficornis Malloch. 

 Glossy upper portion of orbits blue; orbital bristle distinctly proximad of 

 anterior ocellus ; cheek with some short hairs and one or two longer 

 bristles; third antennal segment over three times as long as its greatest 

 width, upper half or more blackened ; hind femur with several long bris- 

 tles on apical half of anteroventral surface winnemanae Malloch. 



11. Ovipositor of female nearly as wide as frons; calyptrae and their fringes 



white; tarsi largely yellowish; scutellum without fine hairs. 



arkansensis Malloch. 



Ovispositor slender, much narrower than frons ; scutellum usually with fine 



hairs in addition to the strong bristles 12 



12. Face and parafacials when viewed from above conspicuously whitish pruin- 



escent ; frons of female dark steel-blue, shining, sparsely and evenly haired, 

 and with a transverse depression midway between anterior margin and 

 anterior ocellus ; third antennal segment but little longer than wide ; a 

 strong curved bristle near anterior margin of cheek ; tarsi slightly pale 

 basally; calyptrae and their fringes brown; no fine hairs on scutellum. 



albiceps Malloch. 



Face but little whitish pruinescent when viewed '/rom above ; frons not 



steel-blue, and without a transverse depression ; cheek either without a 



strong bristle or with several 13 



13. Legs entirely black 14 



At least the bases of tarsi yellowish 17 



14. Fringes of calyptrae brown or fuscous 15 



Fringes of calyptrae white; cheek without strong bristles 10 



15. Cheek with four outstanding bristles ; no hairs between the scutellar 



bristles ; frons slightly bluish or greenish ; third antennal segment about 



1.5 as long as wide quadrisetosa Malloch. 



Cheek without outstanding bristles; some fine hairs between the apical pair 

 of scutellar bristles; frons black angustitarsis Malloch. 



16. Some fine hairs between the apical pair of scutellar bristles. 



vaginalis Fallen. 

 No fine hairs between the apical pair of scutellar bristles. 



marylandica Malloch. 



