12. 
13. 
14. 
15. 
16. 
17. 
18. 
19. 
20. 
21. 
22. 
23. 
24. 
205. 
(9) 
(19) 
HORSEFLIES OF THE SUBFAMILY TABANINAE 39 
Key to Nearctic Females of Tabanus—Continued 
Femora pale reddish Sp gh pase ER ES orbicallus Philip, p. 59. 
ETT OL ae Cai gs Saas ee ee ee St 13 
Hind tibial gage white, with a few black hairs; third antennal 
segment rather elongate; light-gray abdominal spots usually 
rather large and whole body predominantly gray 
intenswus Townsend, p. 60. 
Hind tibial fringe black, with few, if any, white hairs; third 
antennal segment shorter; pale abdominal spots not so large 
and: whole body more black or brown ____=—~-~--__-_-______ 14 
Venter medianly with abundant black hair 
gilanus Townsend, p. 61. 
Venter with no black hair anterior to sternite 6 
laticeps Hine, p. 62. 
Antenna black, the first segment distinctly swollen above; usu- 
ally a few black hairs on side of subeallus 
fairchildi, new species, p. 63. 
Antenna black to yellow, the first segment not strongly swollen 
apoves. side. of <subcallus: without. hairs--2 4 -22_-________ 16 
Robust, dark brown to black, the sublateral, white, abdominal 
spots decidedly larger than the small triangles of median 
TO Wee eee rar MLC eee 2 nivosus Osten Sacken, p. 64. 
Washoutaonis, combination .o£.characters___._____1 22 ___ 17 
Grayish; 12 mm or more in length, with antenna orange except 
for black annulate portion; basal portion of third segment 
very stout; frons somewhat widened above; costal cell 
hyaline; (southwestern part of the United States) 
euryceras Philip, p. 65. 
Notvagreeins: entirely with above -____-______._________________ 18 
Length 12 mm or more, brownish, the frons usually not 
widened above; if less than 12mm, the costal cell infuseated_ 19 
Smaller, dark species, the frons distinctly widened above; costal 
GOMIL TON EWG (eke ee al 2 Tee SSNS a eg a ee ee ee Oe ae 30 
Basal portion of third antennal segment black except at extreme 
eas Greens ee ee ee Oe ee ee eee 20 
Basal portion of third antennal segment mostly orange___-_-__ 22, 
Dorsal excision of third antennal segment deep; second palpal 
segment pinkish, strongly swollen basally, with acute apex; 
fore tibia conspicuously bicolored_____ pruinosus Bigot, p. 65. 
Dorsal excision of third antennal segment very shallow; second 
palpal segment only slightly enlarged basally; fore tibia 
INCI SIM Chy, WLCOlOreGs 2 =~ es Teal Mate OO 21 
Vertex depressed, the surrounding area swollen; frons slightly 
more than four times as high as wide; last antennal annu- 
lus yellowish; triangle on tergite 3 narrowly reaching an- 
PEGIOT IMAG STN sss esr oe et as fulvicallus Philip, p. 66. 
Vertex not distinctly depressed; frons about three and one-half 
times as high as wide; last antennal annulus black; triangle 
on tergite 3 not quite reaching anterior margin 
vivax Osten Sacken, p. 67. 
All wing veins margined with brown; (southeastern part of the 
WinitedgStates) ee ake oe gracilis Wiedemann, p. 68. 
Longitudinal veins, at least, not margined with brown______-____ Fas; 
Third antennal segment uniformly orange brown 
zythicolor Philip, p. 69. 
Annulate portion of third antennal segment black _____-________ 24 
Basal portion of third antennal segment rather short and broad; 
either fureation faintly margined with brown or costal cell 
GeepliyssiMEWSCatedyetms eee we oe ot Bee OE 25 
Basal portion of third antennal segment rather elongate; fur- 
eation not margined with brown and costal cell not deeply 
TO SEDUSCOS HAY 0 Ls Seo Ne EARL ST FAI ee i a esc ee Re, ae ae Pal 
A faint spot at furcation ; costal cell hyaline 
abactor Philip, p. 69. 
INowspot ‘at: furcation ; costal cell infuscated_-2H-_u a 26 
