W. G. DIETZ 347 



Pendulous process larger, tapering from its base; bladelike processes 

 strongly curved laterally, deeply sinuate at base posteriorly; 

 upper process of lateral appendage greatly broadened distally. 

 Joints of flagellum yellowish-fuscous, dark fuscous at base. 



ottawaensis sp. n. 



5. Lower process short, broadly rounded 6 3 



Lower process not so, distal half at least slender, clawlike 7 



6. The upper process ending in two small, subequal dentiform points. 



coloradensis Doane 

 Upper process large, spatulate suspecta sp. n. 



7. Lower process slender, entirely clawlike 8 



Lower process broad in basal half with toothlike projection from its 



under margin doanei sp. n. 



8. Upper process very slender with knoblike enlargement at the apex. 



ingrata sp. n. 

 Upper process not slender, not enlarged at the apex 9 



9. Darker, more grayish; flagellum dark fuscous. Lower process shorter, 



less slender rohweri Doane 



More yellowish; flagellum yellowish fuscous. Lower process very 

 slender grata Loew 



10. The middle process of the lateral appendage entirely membranous, not 



clawlike 11 



Middle process clawlike, entirely chitinized 12 



11. The middle process terminating in an acute spine. Larger. Wing pat- 



tern strongly marked clathrata sp. n. 



Middle process acutely triangular. Smaller. Wings almost unicol- 

 orous derelicta sp. n. 



12. The upper process ending in two small, toothlike projections. 



criddlei sp. n. 

 Upper process single, rounded at tip 13 



13. Bladelike processes broad in basal half, slender apically. Flagellum 



yellow, joints fuscous at base hebes Loew 



Bladelike processes not so formed. Flagellum brown 14 



14. Eighth sternite trilobed; bladelike processes long and slender. Divid- 



ing line of middle mesonotal stripe gray. No fuscous spot at 



base of basal cells alia Doane 



Eighth sternite, emarginate; bladelike processes shorter, more tri- 

 angular. Dividing line of middle mesonotal stripe fuscous. A 

 fuscous spot at base of basal cells newcomeri Doane* 



3 In his table Professor Doane states: "Lower arm of lateral appendage 

 short, broad, flat. . . rohweri;" whereas in the text, it is described as 

 narrow and clawlike. 



4 1 include this species tentatively in the group under consideration. 

 The eighth sternite is not incised on each side. A male specimen, received 

 through the kindness of Professor Doane and bearing his label, does not 



TRANS. AM. EXT. SOC, XL. 



