280 E. T. CRESSON, JR. 



Tibiae mostly black ; abdomen shining, or obscured, at most, only 

 faintly cinereous {subvirescens group) 30. 



30. Post-trochanters with one tooth or appendage beneath 31. 



With two teeth or appendages beneath (Fig. 129) . Western species. 



52. bidens n. sp. 

 With, at most, only minute bristles or tufts of hair beneath 32. 



31. Post-femora with a basal tooth beneath (Fig. 125) ; post-tarsi dis- 



tinctly dilated 51. appeiulipes n. sp. 



Femora without such tooth (Fig 132). ...50. imguiculatus n. sp. 



32. Hypopygium compressed to left 44. coquilletti Kert, 



Hypopygium more or less compressed to right, or small and ap- 

 parently symmetrical 33. 



Hypopygium not compressed, much broader than long, subhemi- 

 spherical (Fig. 105) 47. insularis n. sp. 



33. Abdomen ovate; fifth segment trapezoidal in dorsal outline 34. 



Abdomen subcylindrical ; shining; fifth segment rectangular in out- 

 line (Fig. 108) ' 43. similis Hough. 



34. Abdomen sparingly clothed with fine, brownish pubescence, shin- 



ing ; at most, only ventral margins cinereous. 



42. subvirescens Loew. 

 Abdomen with scattered, black, bristle-like hairs, shining ; at most, 



only ventral margins cinereous 46. scoparius n. sp. 



Abdomen naked, without discernable hair or pile, subopake, or, 

 more or less faintly submetallic, cinereous tinged. 



45. subniteiis n. sp. 



35. Stigma colored, generally long and conspicuous 36. 



Stigma hyaline, or very small 51. 



36. Fourth vein with appendage beyond post-cross vein 37. 



Fourth vein simple and normal 38. 



37. Eastern species; sixth abdominal segment shorter than fifth; 



stigma much shorter than fifth section ; occiput normal. 



25. brevis n. sp. 

 Eastern species ; sixth segment as long as fifth ; stigma equalling 



fifth section ; abdomen shining ; occiput unusually puffed 



out (Fig. 124) 18. appeiidiculatus n. sp. 



Western species ; sixth segment longer than fifth ; stigma shorter 



than fifth section ; abdomen shining.. 9. acuminatus n. sp. 



38. Humeri brown or black 39. 



Humeri yellow or white 43. 



39. Legs entirely yellow ; abdomen broad, distinctly fasciated with gray ; 



antennae acute ; robust species 16. atlantieus Hough. 



Legs yellow except discolored femoral rings ; entire first and second 



segments, and narrow apices of following cinereous. 



20. liiainensis n. sp. 

 Legs mostly black 40. 



