482 Annals Entomological Society of America [Vol. VI, 



156. Color yellow, gray or fuscous 157 



Color black; posterior margin of abdominal segments gray 164 



157. Basal joints of antenna yellow 158 



Basal joints of antennae not yellow 161 



158. Yellowish species 159 



Fuscous species 160 



159. Antennae long, more than half the length of the body, thorax vittate. 



Abdomen brownish. Wings grayish, stigma pale brown. Length 



14 mm disjuncta Walker 



Antennas less than half the length of the body; three vittae of thorax as 

 well as of the abdomen, faintly indicated; eighth sternite extending up 

 on the sides and much produced posteriorly, posterior margin rovmded, 

 with lateral, membranous appendages; ninth tergite very large, 

 posterior angle produced into a pair of thick, heavy, slightly curved 

 horns, posterior margin with two broad, flattened teeth; ninth ster- 

 nite almost concealed by the eighth, posterior margin biemarginate. 

 Wings hyaline, costal and subcostal cells and stigma with yellowish 

 brown tinge. Length 17 mm. ((f') slernata Doane 



160. Abdomen with broad dorsal stripe, basal part of ninth sternite with 



prominent carina. Mesonotum with faint trace of two cinereous lines; 

 posterior margin of abdominal segments gray; hypopygium small, 

 posterior margin of ninth tergite with crescent shaped incision; ninth 

 sternite with crescent shaped incision. Wings with brownish tinge, 

 subcostal cell and stigma slightly darker brown. Length 13-16 mm. 



carinata Doane 

 Abdomen with lateral and ventral stripes; ninth sternite not carinate. 

 Mesonotum with three indistinct vitts; posterior margin of abdominal 

 segments paler; ninth sternite ending in two short, blunt points; ninth 

 sternite with deep incision, containing a pair of long, membranous 

 appendages. Wings with slight grayish tinge, stigma and veins brown 

 the fifth posterior cell is not in contact with the discal cell. Length 

 13-15 mm sulphurea Doane 



161. Gray species 162 



Fuscous species 163 



162. Thoracic stripes margined; lateral and posterior margin of abdominal 



segments margined with yellowish. First antennal joint gray. Hypo- 

 pygium medium sized; ninth tergite large, convex, narrowed poster- 

 iorly and terminating into a short, rounded process; ninth sternite 

 very large, protuberant, narrowly divided, subcarinate in its basal 

 half, about the middle of the incision is a slight protuberance, densely 

 covered with short hair; pleural suture nearly straight, evavescent 

 posteriorly. Wings pale brownish, somewhat infuscate at the apex, 



veins and stigma brown. Length 8 mm. (cf). cincta Loew 



Thoracic stripes not margined, lateral ones ill defined; abdomen with 

 fuscous dorsal and ventral stripe. Head and thorax more or less 

 clothed with pale, erect soft hairs. Hypopygium small. Wings with 

 whitish tinge, veins and stigma brown. Length 9-13 mm. . . .besselsi O. S. 



163. Head with two small, tumid processes just above the base of the anten- 



nae; abdomen with three dark fuscous stripes, posterior margin of seg- 

 ments paler. Mesonotum gray with five fuscous stripes. Hypopy- 

 gium small, ninth tergite with U-shaped incision; ninth sternite with 

 deep narrow incision. Wings with grayish tinge, somewhat darker 

 along the veins and in the middle of the cells, stigma brown, praefurca 



short. Length 10-14 mm biturberculata Doane 



Head without processes, dorsal abdominal stripe, if at all, very faint. 

 AntenncB rather long; mesonotum with median black line and two 

 lateral indistinct, paler lines. Eighth tergite concealed except later- 

 ally; hypopygium very small, ninth tergite with wide, crescent shaped 

 incision; ninth sternite with lateral appendages. Wings uniformly red- 

 dish-brown, stigma concolorous, veins brown. Length 9-10 mm. (cf )• 



illustris Doane 



