HORSEFLIES OF THE SUBFAMILY TABANINAE 153 
parallel, outer margins oblique, reaching to lateral margin and slightly widened 
there; venter dark gray, the incisures paler. 
Male.—Unknown. 
Type.—In the collection of the University of Minnesota. 
Type locality.—Greenbush, Minn. 
Distribution.—Known from single type specimen. 
The type is apparently considerably rubbed, and it is probable that 
good specimens would show the light-gray pollen on frons, thorax, 
and abdomen to be more extensive. 
TABANUS RHOMBICUS Osten Sacken 
(Kig. 74, B) 
Tabanus rhombicus Osten Sacken, Mem. Boston Soc. Nat. Hist. 2 (pt. 4, No. 4): 
472, 1876; U. S. Geol. and Geogr. Survey Terr. Bull. 3: 218, 1877; Hine, Ohio 
Nat. 5: 242-243, 1904; Cameron, Bull. Ent. Research 17: 86-37, 1926; Rowe 
and Knowlton, Canad. Ent. 67: 248-244, 1985; Philip, Canad. Ent. 68: 152- 
1538, 19386. 
Tabanus centron Marten, Canad. Ent. 14: 211-212, 1882: Hine, Ohio Nat. 5; 235, 
1904; Philip, Canad. Ent. 67: 94-95, 1985; Rowe and Knowlton, Canad. Ent. 
67; 241, 1935. 
Tabanus osburni Hine, Ohio Nat. 5: 241, 1904; Philip, Minn. Agr, Expt. Sta. 
Tech. Bull. 80: 114, 1981; Rowe and Knowlton, Canad. Ent. 67: 248, 1925; 
Philip, Canad. Ent. 68: 153, 1936. 
Hybomitra solow Enderlein, Mitt. Zool. Mus. Berlin 10: 347, 1922; 11: 364, 1925. 
(New synonymy. ) 
Rather small, stout; black, with three rows of gray triangles on abdomen 
sometimes evanescent, the sublateral spots little, if any, reddened ; prescutal lobe 
black; subeallus black, denuded; third antennal segment rather long, slender. 
Female.—Length 12-16 mm. Hye pilose, purple, with four narrow, blue-green, 
diagonal stripes. Frons gray, about three times as high as basal width, dis- 
tinctly widened above; basal callus shiny chestnut brown to black, convex, sub- 
quadrate, usually touching eyes; median callus small, ovate, black, usually with 
a slender line to vertex and another to basal callus; a large, partially denuded 
ocellar tubercle at vertex; subeallus entirely denuded, concolorous with basal 
callus. First two antennal segments yellow brown to black, the first with long 
black hair; third usually orange brown at least basally and this color occasion- 
ally covering most of basal portion, the remainder black; basal portion long and 
slender, with low dorsal angle and no excision. Clypeus and genae light gray, 
with whitish hair. Palpus yellowish brown, with concolorous hair and second 
segment with short black hair; second segment moderately stout basally. 
Thorax entirely black or dark gray, the dorsum with narrow gray lines in 
usual pattern, erect black hair, and some recumbent, pale-yellowish to whitish 
hair; pleura and coxae with mostly yellowish-white hair. Wing hyaline, the 
costal cell often faintly brownish; venation normal. Legs brownish black, the 
tibiae slightly lighter basally, with short yellowish hair ; hind tibial fringe short, 
black. 
Abdomen above black, with three rows of usually distinct, dull grayish spots; 
median triangles not reaching anterior margin of tergites; sublateral triangles 
with outer margins oblique and reaching lateral margins; venter rather uni- 
formly dull grayish. 
Male.—Hye with dense, long pile, the facets nearly uniform in size; antenna 
black; second palpal segment stout, with blunt apex, yellowish brown, the under 
surface darkened. Body coloration essentially as in female, the entire thorax 
black, Subshiny. 
Type-—A. specimen labelled type by Osten Sacken, one of four 
cotype females in the Museum of Comparative Zoology, No. 4030, 
herein designated as the lectotype. One of the cotypes is Zabanus 
hirtulus (Bigot). 
Type locality—Colorado. 
