7. Hyaline triangle attains posterior margin of wing (fig. — 

 14:47c) 8 



— Hyaline triangle enclosed, not attaining posterior 23 



margin of wing; Los Angeles County 



fulvaster Osten Sacken 1877 



8. Knob of halter brown or black; scape not incrassate; 

 Plumas County to San Bernardino County — 



coloradensis Bigot| 1892 



— Knob of halter yellow; scape incrassate 9 



9. First segment of flagellum distinctly longer than the 

 sum of the 4 apical segments; outer margin of cross- 24 

 band sinuous with toothlike projections in cells R 3 and 



Mj virgulata Bellardi 1859 



— First segment of flagellum not longer than the sum of 



the 4 apical segments; outer margin of crossband — 

 evenly convex or with no projection in R 3 10 



10. Apical spot of wing exceeds vein R 5 ; Madera County 

 to San Diego County clavicornis Brennan 1935 



— Apical spot of wing not exceeding vein R 5 , as a rule 25, 

 occupying about half of cell R 4 11 — 



11. Second tergite typically with double geminate black 

 spot; outer margin of crossband sinuous; Ventura and 26. 

 Los Angeles counties robusta Brennan 1935 



— Second tergite with single geminate spot; outer margin — 

 of crossband straight 12 27 



12. Scape much enlarged, widest diameter almost twice 

 that of pedicel (fig. 14:47e); Shasta County to San 

 Diego County coquillettii Hine 1904 — 



— Scape enlarged, but widest diameter not much more 28, 

 than pedicel 13 — 



13. Tergites caudad from 3 with black lateral spots; Contra 29. 

 Costa County pachycera hungerfordi Brennan 1935 



— Tergites caudad from 3 without black lateral spots; — 

 San Diego County . pachycera pachycera Williston 1887 



14. Cell 2M infuscated over at least half its length; tergites 

 with no yellow on mid-line 15 30, 



— Cell 2M hyaline, although there may be some infusca- 

 tion at base and apex; tergites with yellow markings on 

 mid-line and posterior margins 17 — 



15. Dorsum of abdomen with orange spot on anterolateral 

 margin; Lassen County to Calaveras County 31. 



noctifera noctifera Osten Sacken 1877 — 



— Dorsum of abdomen black 16 



16. Crossband abbreviated in cell M 3 and with a distinct 32. 

 toothlike projection from the crossband in cell R 3 ; — 

 Humboldt County to Marin County 33, 



noctifera pernnax Williston 1887 



— Crossband practically complete to hind margin of wing — 

 and without a toothlike projection; Marin County to San 

 Luis Obispo County pechumani Philip 194 1 34. 



17. Radial cell hyaline, although possibly with a small — 

 amount of infuscation at base and apex 18 35. 



— Radial cell infuscated over more than 1/2 its area .. 19 



18. First tergite black, posterolateral margins may be gray — 

 aestuans van der Wulp 1867 



— First tergite yellow with brown quadrate spot on antero- 36. 

 median margin; Modoc County to Inyo County 



bishoppi Brennan 1935 — 



19. Discal cell (first M 2 ) infuscated 20 



— Discal cell hyaline, although possibly infuscated 37. 

 around borders; Del Norte County to Inyo County . . . 



. . discalis Williston 1880 



20. Second tergite with a small black anteromedian quadrate 



or reniform spot, the remainder of the segment yellow; — 

 face black with 3 yellow pollinose stripes; Shasta, 

 Plumas, and Sierra counties asbestos Philip 1949 38. 



— Second tergite otherwise marked; face with some 

 integumental yellow 21 — 



21. Radial cell with an infuscated band for its entire 

 length, sometimes dilute toward outer two-thirds; a 39. 

 narrow hyaline line on posterior border, widest apically; 



fore coxae black 22 — 



— Radial cell with apical 3rd hyaline; fore coxae yellow 40. 

 furcata Walker 1848 



22. Second tergite with an isolated black spot laterad to 

 geminate spot (fig. 14:476) 23 — 



447 

 Wirth and Stone: Diptero 



Sides of 2nd tergite entirely yellow or the b 



enlarged ami connei ted with the median figure 24 



.Apical spot beyond era band narrow, not ■■ : 

 the basal width of cell M,; yellow tripi 

 clypeus narrow; Siskiyou Count) to lular" Count) .. 



1 877 



Apical spot beyond crossband wide, about twice the 



basal width of fell M,; yellow ;m,i .,ii fronl 



wider than lateral brown lobei (Humboldt to Tulare 



counties) proclivis proclivis <) •< 1-77 



. Tergite 3 with 4, more or less di 

 yellow spot on frontoclypeus wider than lateral brown 



lobes; Plumas County, to Tulare County 



proclivis imfurcata Philip 1935 



Tergite 3 black except for narrow Hi tripe near 



incisure; yellow spot on front oi l\|>< luced to a 



very narrow line; Fresno County 



proclivis pice a Philip 1935 



Apex of the wing beyond the crossband hyaline 26 



Apex of the wing beyond the crossband more or less 



infuscated 29 



Base of cell Cu, typically with a hyaline spot 



carbonaria Walker 1848 



Base of cell Cu, infuscated 27 



, Tergites with some yellowish pubescence, especially 



near the apex and forming median triangles 



excitans Walker 1848 



Tergites black pubescent 28 



Mid-tibia black mi/is Osten Sacken 1 s7") 



Mid-tibia reddish brown hirsnt.ic alius Philip 1941 



Apical spot approximately the same width for its entire 



length; including only the apex of cell R 4 30 



Apical spot not as above, variable, usually including 

 nearly 1/2 of cell R 4 , often extending considerably 



beyond middle of cell 34 



Wholly black species; frontoclypeus black; apical spot 



practically separated from crossband 



noctifera pertinax Williston 1887 



Not wholly black species; frontoclypeus yellow; apical 



spot distinctly united with the crossband 31 



Frontoclypeus and oral margins of genae yellow .... 32 

 Frontoclypeus and oral margins of genae not entirely 



yellow, usually with a black spot on each side 33 



Wing picture dilute bishoppi Brennan 1935 



Wing picture saturate aestuans van der Wulp 1867 



Frontoclypeus black with a narrow yellow mid-streak 



surda Osten Sacken 1877 



Frontoclypeus yellow with a black spot on each side 



proclivis proclivis Osten Sacken 1877 



Antenna incrassate (distinctly swollen) 35 



Antennae not incrassate 41 



Annulate part of flagellum much shorter than scape 



virgulata Bellardi 1859 



Annulate part of flagellum not shorter than scape, 



usually longer 36 



Apical spot of the wing extending at least into cell R s 



37 



Apical spot of the wing not extending beyond vein R s , 



usually not even attaining this vein 38 



Antenna yellowish, the scape distinctly bottle-shaped; 

 second tergite yellow with a median broad black 



geminate figure and a black spot on each side 



clavicornis Brennan 1935 



Antenna black, scape not bottle-shaped; 2nd teruite 

 not patterned as above . . . fulvaster Osten Sacken 1877 

 Second tergite with a double geminate black fieure 



robusta Brennan 



Second tergite without a double geminate black figure 



.39 



Second tergite with lateral black spots 



pachycera hungerfordi Brennan 1935 



Second tergite without lateral black spots 40 



Cell 2M infuscated subequally with R; crossband some- 

 times fenestrated; tergites 3 and 4 rarely with a black 

 spot on each side. . .pachycera pachycera Williston 1887 

 Cell 2M infuscated about 1/2 that of R; crossband 



