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Key to Nearctic Females of Tabanus—Continued 
Pale spot on tergite 2 distinctly smaller than those on tergites 
3 and 4; scutellum with distinct pale pile; fore tibia nearly 
nMitormin-color. =: 325 at ee fe ee 
Not. with-above combination of characters=—_-—=- 2-2 
Abdominal triangles large and‘ broags.24222 30 eee 
Abdominal triangles small_-__-- superjumentarius Whitney, p. 99 
Frons less than five times as high as width at base, only mod- 
erately widened above; veins Ri and Re: not distinctly mar- 
gined with brown; mid and hind tibiae pale reddish brown, 
the apices not markedly darker__________ molestus Say, p. 97. 
Frons more than six times as high as width at base, consider- 
ably wider above; veins R: and R»-; distinctly margined with 
brown; mid and hind tibiae creamy white, the extreme 
apices dark brown to black_-__moderator, new species, p. 98. 
Fureation not margined with brown, or, if a faint spot is present, 
there is also a stump vein. at-furcationi=-—__-- = 2 . 
Furcation distinctly margined with brown, stump vein rarely 
DUCSONT Sas on re Se ak ae ke eee 
Rather small, compact, not over 15 mm long, dark reddish brown, 
the pale abdominal triangles arising from narrow bands; 
subcallus denuded or very thinly pollinose; fore tibia not 
markedly bicolored, although there may be pale hair basally 
coffeatus Macquart, p. 100. 
Without this combination of characters___________-___________ 
Kore: tibia uniform. in’ STound = COlOr = oe a ee ae re ee EY 
Fore, tibia distinetly, bicolored = = ere 2 ae ee ee ee 
Costal cell hyaline; (dusty reddish brown, the median abdominal 
triangles: faint) =.24 Sh. 22s ee rufofrater Walker, p. 101. 
Costatl. cell -distinethy- colored: 2 3 2 oe ae ee ee ee 
Third antennal segment with considerable black; abdominal 
triangles small but rather distinct, narrow, not arising from 
bands; cell Rs not narrowed toward margin 
catenatus Walker, p. 102. 
Third antennal segment mostly red; abdominal triangles very 
faint, but arising from faint bands; cell Rs somewhat 
narrowed toward margin-___________ giganteus Degeer, p. 84. 
Abdominal triangles small and narrow on tergites 3 and 4; 
palpus reddish brown; (length over 18 mm) 
actaeon Osten Sacken, p. 1038. 
Abdominal triangles large and broad on tergites 3 and 4; palpus 
yellowish wiite.. 2. 3. ee Je ee he ee eee ee 
Vein Rs with stump; hind tibia nearly half black; fureation 
faintly margined with brown_____-_-__ lacustris Stone, p. 104. 
Without this combination of. characters 22225535 2 
Median triangle on tergite 2 slightly expanded anteriorly; cell 
R; closed and petiolate; hind tibia uniformly yellowish, with 
DLAGK © Pets 2a ere cee Os a ere petiolatus Hine, p. 105. 
Median triangle on tergite 2 not expanded anteriorly and often 
not reaching anterior margin; cell Rs usually narrowed or 
just closed; hind tibia with extreme apex usually blackened 
melanocerus Wiedemann, p. 106. 
Fore tibia unicolorous or rarely the base brownish, with orange 
black hair, the apenx darker. = 2 ee ee 
Fore tibia distinctly bicolored, the basal portion light, with pale- 
yellowish, hair... + 2 = ew hi ee ee eee 
Venter of abdomen black, with strongly contrasting, rather broad 
bands; (tibia bright orange, with concolorous hair) 
trijunctus Walker, p. 107. 
Venter of abdomen brownish, the pale bands, if present, not 
strongly contrasting, or, if venter is black, the bands very 
TAT TOW a a he 5 ae rey eee 
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