468 Annals Entomological Society of America [Vol. VI ^ 



51. Dark cinereous; abdomen sordid testaceous, indistinctly trivittate, last 



two segments blackish, lateral margins of segments whitish. Hypopy- 

 gium small, ninth tergite reniform. Wings grayish-fuscous, a small 

 white spot at the posterior margin of the second basal cell, discal cell 

 and base of fourth posterior cell indistinctly whitish. Length 14 mm. 



centralis Loew 

 Yellowish; thorax reddish; abdomen trivittate. Hypopygium moder- 

 ately large, ninth tergite membranous posteriorly, deeply emarginate 

 in the middle, sides deflected in the form of rounded lobes; ninth 

 sternite entire, a somewhat ellipsoidal shaped process arises from its 

 posterior margin. Wings strongly tinged with yellow. Length 

 10-24 mm flavescens Fabr 



52. Joints of flagellum unicolorous 53- 



Joints of flagellum bicolorous 60" 



53. Color grayish 54 



Color not grayish 57 



54. Three white spots along the posterior wing-margin; middle thoracic 



vitta obsolete anteriorly. Abdomen testaceous, lateral margins and 

 last segments fuscous; hypopygium subcarinate below; wings grayish. 



Length 9-13 mm fragilis cf Loew 



suspecta 9 Loew 

 Posterior wing margin without three spots 55 



55. Scutellum and metathorax shining; former yellow with a brown line in 



the middle. Abdomen brownish yellow, hind margin of segments 

 and interrupted dorsal stripe brown; hypopygium rather large, ninth 

 tergite broader than long, posterior margin with a crescent shaped 

 emargination; ninth sternite nearly completely divided; pleural suture 

 almost extending to the anterior margin. Wings pale gray, veins of 



apical portion white margined. Length 7-16 mm beatula O. S. 



Scutellum and metathorax not shining 56- 



56. Abdomen shining, sutures brown, wings with three clearly defined 



fuscous spots along the costal margin. Length 18 mm,. . . .frigida Walker 

 Abdomen trivittate; wings with three fuscous spots along the costal 

 margin near the apex. Length 12 mm resurgens Walker 



57. Pubescens of body very conspicuous. Testaceous; thoracic stripes not 



very distinct. Hypopygium very large; ninth sternite large, barbed 

 at the posterior margin with golden yellow hair. Wings grayish 

 fuscous, anterior branch of second longitudinal vein abbreviated; 

 most of the veins margined with fuscous; all posterior cells white 



margined. Length 18 mm pubera *Loew 



Pubescens of body not conspicuous 58 



58. A whitish spot before and behind the stigma 59 



Wings not so marked. Brown; mesonotum with four brown stripes; 



abdomen with lateral stripes, latero-posterior margins of segments 

 yellowish; eight and ninth segments separated above by a deep furrow; 

 lateral margins of ninth tergite drawn out into a blunt point posterior- 

 ly, ninth sternite divided by a deep quadrate incision. Veins in apical 

 part of wing white margined, and tipped with fuscous; similar to 

 commiscibilis (contaminata). Length 22 mm. (9) abluta fDoane 



59. The white spot before the stigma extends to base of fourth posterior cell; 



abdomen trivittate 60' 



The white spot before the stigma does not extend to the posterior cells. 

 Brownish yellow. Mesonotum with four broad, brown stripes; 

 abdomen with broken, brown lateral stripe; ninth tergite with deep, 

 median furrow and rather deep V-shaped incision, the apex of which 

 bears a short triangular black tipped tooth; ninth sternite with broad, 

 deep U-shaped incision which contains a pair of large, tumid yellow 

 haired appendages. Veins with indistinct whitish border. Length 

 16 mm calif ornica Doane 



* Should have been placed under 37. 

 t Should have been placed under 37. 



