26. 
27. 
28. 
29. 
30. 
ol. 
ENTOMOLOGY 909 
. Larger and darker species, 17 to 30 mm. long, usually mahogany brown to black; anten- 
nae dark brown to black. Frons six to seven times as long as wide, distinctly nar- 
rowed toward the subcallus. Fore tarsi widened.............0cceeeecceeeeneees 24. 
Smaller and generally of a lighter color, 10 to 17 mm. long, the abdomen reddish yellow to 
reddish brown; antennae bright yellowish red to brownish. Fore tarsi slender.... 25. 
. Abdomen mahogany brown, without bluish gray bloom, slightly shiny. Length, 17 to 
ESP OUUE Aa tect aey Mate err Mie Raises Croan Soe ec lh yet wach nial ears T’. fuscomarginatus. 
Abdomen more blackish brown, dull, densely covered with a bluish gray bloom. Length, 
COM MMMM MCU LORE: Cc a aoe wun csttm sin dace & <tedis ges Lava Ge eevee ¥ T. ruficrus. 
. Legs mostly reddish yellow, especially the fore femora; fore tibiae pale yellow or whitish, 
their apices and the fore tarsi black. Wing faintly tinged with yellow. Frons about 
five times as long as wide, scarcely narrowed toward the subcallus. Length, 11 to 
DO a ereie aaeur eee ane, fon, rh orcas eemeaaonnig hs en aie aia ae deahka T.. thoracinus. 
Legs extensively blackish or dark brown, especially the fore femora.................. 26. 
Darker, with the wings suffused with brown, especially toward the anterior margin; the 
veins brown; all the femora dark brown with black pile; palpi dark brownish yellow, 
with black hairs; pile of the lower part of the face dark brown. Frons five to six 
times as long as wide, scarcely narrowed toward the subcallus. Length, 13 to 
MOM ONIC ia, ee ahreecy ea ere NG VA cade, Red oh aA Woe’ aide ey oe ete mye avs Alcina S T.. obscurtor. 
Lighter, with the wings suffused with yellow, especially along the anterior margin; the 
veins yellowish; fore femora dark brown to blackish; middle and hind femora red- 
dish brown, with yellowish pile; palpi pale reddish yellow, mostly with yellowish 
hair; pile of the lower part of the face reddish yellow. Frons five to five and one- 
half times as long as wide, scarcely narrowed toward the subcallus. Length, 13 to 
LET Oe 6 aes FR eons 2) Ree rere fe Rem e ( eOe em n kOe er T. obscuripes. 
Group G (Tabanus, proper, in part) 
Brownish red to black, densely covered with white, silvery, appressed pubescence leaving 
indistinct, darker, longitudinal stripes on the dorsum of the thorax and four triangu- 
lar, brown spots at the anterior margins of the third to sixth abdominal tergites. 
Legs pale reddish brown, the tarsi darker. Wing subhyaline, slightly clouded along 
the reddish yews: Length, 20 to 250MM. ec. ie cee ec ews dees See. T. canus. 
Body not mostly clothed in silvery white pubescence; the abdomen not with four tri- 
angular spots at the anterior margins of the tergites.................00e cece ecee 28. 
Wing more or less distinctly and extensively marked with hyaline or paler spots or streaks 
on a dark brown or black background; a paler triangle filling the distal portion of the 
SEC OMICS MARIE MINN COLL ay GNI Sire erie tem HA Shis afoceis le ed Wwe sa AEE Ll ae ee eins 29. 
Wing either hyaline throughout, or uniformly infuscated, or with the anterior margin 
darker or more yellowish, or infuscated with paler apex, or smoky or spotted on 
sy Gra AAU HET UUTECIA conta escyet ccat ts ri My mrt eras AMER Oe ec ade soe TN mitt & bey WM oe RE oy ecw 32. 
Abdominal tergites without median, white spots; first tergite pale brown and entirely 
covered with golden yellow pile; the three following tergites with narrow, pale, 
apical margins covered with white or yellow pile; the second to fifth sternites with 
wider, pale, apical margins. Legs black, the basal half of fore tibiae white. Pale and 
dark markings of the wing very distinct. Length, 17 to 20 mm........ T. billingtoni. 
Second to fifth abdominal tergites with large or small spots of white pile.............. 30. 
First and second abdominal tergites mostly covered with silvery white pubescence; the 
second with a median, oval or crescent-shaped, black area and on each side with a 
dark spot in the extreme anterior corner; the three following tergites each with a 
low, more or less triangular, median, white spot on the hind margin, that of the 
fourth continued as a fringe to the hind corners where it widens into a spot; second 
to sixth sternites with conspicuous, lateral, white spots, faintly connected along the 
hind margins. Legs black, the fore tibiae with some white pile on their basal two- 
thirds. Pale and dark markings of the wing very distinct. Length, 10 to 23 mm. 
le Ss AAA EP CEPI, eR AG SPER a Re eer ee T’. marmorosus var. congoicola. 
All the dorsal tergites each with a small or large, median, white spot on the hind margin. 381. 
Pale and dark markings of the wing very distinct; basal half of first submarginal and first 
posterior, as well as most of the discal cell, clear, forming a transverse band which 
