HORSEFLIES OF THE SUBFAMILY TABANINAE 159 
Type.—A female in the collection of the University of Minnesota. 
Paratype also in the University of Minnesota collection. 
Type locality.—Itasca Park, Minn. 
Distribution.—Known only from the type locality. 
TABANUS ATROBASIS McDunnough 
(Fig. 77, B) 
Tabanus atrobasis McDunnough, Canad. Ent. 53: 144, 1921. 
Medium sized, stocky; dark brown or blackish, with orange or reddish on 
sides of abdomen not reaching across first tergite; palpus stout, yellowish 
brown; subcallus pollinose; prescutal lobe black. 
Female.—Length 15-17 mm. Eye densely pilose, with four diagonal green 
stripes on a deep-purple ground. Frons three to three and one-half times as 
high as width at base, somewhat widened above, yellowish gray; basal callus 
shiny black, subquadrate, not quite touching eyes; median callus small, usually 
connected by a slender line to basal callus and ocellar tubercle; the latter with 
gray pollen or denuded, nearly as wide as vertex but not sharply defined; sub- 
eallus rather flat, yellowish gray. Antenna mostly black, the first two segments 
reddish brown, with black hair, the third reddish at extreme base; basal portion 
of third rather elongate, dorsal angle short and obtuse and dorsal excision very 
shallow or absent; annulate portion much shorter than basal portion. Clypeus 
and genae yellowish gray, with a mixture of white, yellowish, and black hair. 
Second palpal segment moderately stout, tapering, yellowish brown, with short 
black hair. 
Mesonotum, including prescutal lobe, black, with five faint brownish lines. 
Pleura, sternum, and coxae dark gray, the hair black except around wing base 
and on coxae. Wing nearly hyaline, the costal cell tinged with orange brown, 
veins brown and a small spot at furcation; venation normal. Femora black; 
tibiae dull orange to black, the fore tibia gradually darkened apically; tarsi 
dark orange brown to black. 
First abdominal tergite black except for a narrow posterior margin of orange; 
sides of tergites 2-4 orange brown, with faint, yellowish, diagonal triangles, 
leaving a rather broad, median, black stripe narrowing to tergite 4 and bearing a 
median row of rather distinct, small, yellowish triangles; tergites 46 dark 
brown to black; venter orange brown, darker apically. 
Male.—Hye densely pilose, the facets nearly uniform in size; second palpal 
segment stout, dark orange brown, with black hair. Coloration essentially as in 
female, the frontal triangle gray and genae dark gray, with mostly black hair. 
Described from a specimen collected at Moscow, Idaho, July 25, 
1920, by R. C. Shannon. 
Type.—A female in the Canadian National Collection. * Paratypes 
also in the Canadian National Collection and three in the Museum of 
Comparative Zoology. 
Type locality—Mount Lehman, British Columbia. 
Distribution.—British Columbia to New Mexico. May 30 (Mt. 
Lehman, British Columbia) to July 25 (Moscow, Idaho). In the 
United States National Museum, 10 females, 1 male. 
TABANUS HIRTULUS (Bigot) 
(Fig. 78, A) 
? Therioplectes tetricus Marten, Canad. Ent. 15: 111, 18838. 
Therioplectes hirtulus Bigot, Mem. Soc. Zool. France 5: 641-642, 1892. 
Tabanus frenchii Hine (not Marten), Ohio Nat. 5: 237, 1904. 
Tabanus opacus Hine (not Coquillett), Ohio Nat. 5: 240-241, 1904. 
Tabanus hirtulus Hadwen, Brit. Columbia Ent. Soc. Proc. 4 (n. s.): 48, 1914; 
Cameron, Bull. Ent. Research 17: 27-28, 1926; Rowe and Knowlton, Canad. 
Ent. 67: 242, 1985; Philip, Canad. Ent. 68: 155, 1936. 
? Tabanus tetricus Philip, Canad. Ent. 67: 93, 1935. 
Medium sized; blackish, with three rows of gray spots on abdomen, the 
sublateral spots often tinged with brown; prescutal lobe yellowish brown; 
