64 MISC. PUBLICATION 305, U. S. DEPT. OF AGRICULTURE 
21 (McCurtain County, Okla.). Specimens from Connecticut, and 
Arkansas have also been seen. 
Graham Fairchild pointed out to the writer that the type male 
of Osten Sacken’s Zabanus vivax does not agree with the species 
called vzvax by Hine and others. The writer takes great pleasure in 
naming this long recognized, but misdetermined, “river horsefly” in 
his honor, This species is remarkable in that the entire larval stage 
is spent under stones in rapidly running water, whereas the larvae 
of most species live in mud. 
TABANUS NIVOSUS Osten Sacken 
(Fig. 20, A) 
Tabanus nivosus Osten Sacken, Mem. Boston Soc. Nat. Hist. 2 (pt. 4, 
No. 4) : 445-446, 1876; Cameron, Bull. Ent. Research 17: 32-33, 1926; Stone, 
Ann. Ent. Soc. Amer. 28: 298, 1930; Philip, Minn. Agr. Expt. Sta. Tech. 
Bull. 80: 31, 112, 1931. 
Rather small, stout; brownish black, with three rows of white spots on 
abdomen, the sublateral spots very large and the median triangles very small; 
no spot at furcation. 
“[\ = 
Ficure 20.—Antenna, frent view of head, and palpus of (A) Tabanus nivosus and (B) 
T. euryceras. 
Female.—Length 11-14 mm. Eye bare. Frons brownish gray, darker at level 
of median callus, three to three and one-half times as high as width across 
basal callus, with nearly parallel sides; basal callus yellowish to dark brown, 
fiat and somewhat roughened, square and not touching eyes: median calius 
a slender, somewhat darker projection from basal callus reaching about to 
middle of frons; subcallus and upper genae light brown. First two antennal 
segments yellow brown, with black hair: third dark brown to black, with 
searcely any excision and dorsal angle distinct but obtuse; annulate portion 
slightly shorter than basal portion. Clypeus and genae light gray, with white 
hair. Second palpal segment light yellowish brown, with black and yellowish- 
brown hair, moderately stout at base and tapering to a slender apex. 
Mesonotum black, with orange-brown prescutal lobe and brownish-gray lines 
in usual pattern. Pleura, sternum, and coxae yellowish brown to dark gray, 
with mostly white hairs except on supraepimeron, where they are black. Wing 
hyaline, the veins brown; venation normal. Legs yellowish brown to dark 
brown, the femora, apices of tibiae, and the tarsi darkened; hair of tibiae 
mostly white, the hind tibial fringe weak. 
Abdomen dark brown to black, with white markings consisting of a median 
row of very small triangles and sublateral rows of large, oblique spots, the 
sublateral spot on second tergite broadly touching both anterior and posterior 
margins; sublateral spots often tinged with yellowish brown; venter dark 
gray. 
Male——Areas of large and small facets of eye distinctly but not greatly dif- 
ferentiated. Whole head brownish, with brownish hair. Pleura and sternum 
dark brownish, with dark-brown hair. Legs darker than in female. Abdominal 
coloration as in female. 
Type.—The female herein designated as the lectotype from a pair 
in the Museum of Comparative Zoology (No. 4041). 
Type locality —New Jersey. 
