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D. (3) 
MISC. PUBLICATION 305, U. S. DEPT. OF AGRICULTURE 
Key to Nearctic Males of Tabanus—Continued 
Wing, heavily,, infuseated = 22226). ea ee ee 
Wing hyaline or nearly so_____--_-_~- aegrotus Osten Sacken, p. 90. 
Wa & Dye Gig es era ee atratus Fabricius, p. 87. 
Wing yellowish along posterior margin 
atratus var. nantuckensis Hine, p. 89. 
Scutellum and lateral margins of mesoscutum with white pile 
punctifer Osten Sacken, p. 93. 
Seutellum and lateral margins of mesoscutum without white pile__ 
Genge STay = 2 oe a ee ee prozimus Walker, p. 91. 
Genre .dark., BrOWn «2-222 23 2s ee ee ee ee 
Wing dark brownish___-_~_~_~ nigrescens var. atripennis Stone, p. 93. 
Wine. subhyaline,. yellowish. 2.2... 22s. st er I nD ee 
Antenna, including annulate portion, orange____stygius Say, p. 94. 
Antenna, or at least annulate portion, blackish___._____________ 
Lower margin of area of large facets of eye about on level with 
top: of antennal pits.~ 2. 2 2 subniger Coquillett, p. 95. 
Lower margin of area of large facets somewhat higher 
nigrescens Palisot, p. 92. 
Abdomen orange brown, with a median dark stripe; (wing fumose 
or spotted with brown) -—-----~- fumipenins Wiedemann, p. 96. 
Abdomen either with conspicuous bands or with a median stripe 
or row of pale spots, with or without sublateral spots_____-__ 
A median row of pale triangles or spots on abdomen not forming a 
parallel-sided stripe; no distinct sublateral spots although 
there may be broad bands which tend to obliterate the median 
Greed Ss ee a a ee 
Abdomen. otherwise marked. =.=... _- es ss Poke ee 
Very distinct, white, median triangles on tergites 3-5 and rarely 
a faint one on tergite 2; fore tibia bicolored; venter of abdo- 
men with a distinct, median, brown stripe; furcation and cross 
veins faintly margined with brown_trimaculatus Palisot, p. 96. 
INGE GS DONG 22m 2 2 es ee ee ee Soe 
Hurention not _marzined With DEO Wil 22] 2 es ee eee 
Furcation with a more or less distinct brown spot___-__________ mee 
Scutellum with distinct white pollen and pile, contrasting with the 
darker base of abdomen; (costal cell yellowish brown) 
: molestus Say, p. 97. 
Scutelum without white pollen and pile except around margin___ 
Frontal triangle denuded and somewhat protuberant 
coffeatus Macquart, p. 100. 
Frontal triangle not denuded or swollen-_________________________ 
Median triangles of abdomen nearly obliterated by very broad, pale 
bands nearly covering tergites 3 and 4; thorax very dark brown 
in contrast to pale abdomen; scutellum dark, with pale margin; 
costal .cell: hyaline=- 2 =<s225 rufofrater Walker, p. 101. 
Not with. this combination. of, characters2=— 22.2 32s ae ee eee 
Median triangle on tergite 2, if present, much smaller than those 
Oo ANG 4. a ee eee superjumentarius Whitney, p. 99. 
Median triangles on tergites 24 of about equal size______________ 
Upper facets of eye not much larger than those below 
giganteus Degeer, p. S84. 
Upper facets of eye much larger than those below, the line of 
differentiation. pronounced ..= << =. a ee 
Remora plac ke eee es melanocerus Wiedemann, p. 106. 
HWemora. orange, Drown. 2 oo 2 es ea ae ee 
Frontal triangle, clypeus, and genae grayish white; fore tibia some- 
what paler basally than apically; abdomen rather broadly 
orange brown laterally, the median row of triangles on 2 
narrow, blackish, median stripe__actaeon Osten Sacken, p. 1038. 
Frontal triangle, clypeus, and genae yellowish brown: fore tibia 
uniform in color; abdomen uniformly dark reddish brown 
except for median row of small, pale triangles 
catenatus Walker, p. 102. 
gta 
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