HORSEFLIES OF THE SUBFAMILY TABANINAH 117 
TABANUS ACUTUS (Bigot) 
(Fig. 55, A) 
Atylotus acutus Bigot, Mem. Soc. Zool. France 5: 660, 1892. 
Tabanus acutus Hine, Ohio Nat. 7: 22, 1906; La. Agr. Expt. Sta. Bull. 98: 
40-41, 1907. 
Medium sized, slender; yellowish brown, with a broad, pale, parallel-sided, 
median stripe on abdomen; a small infuscation at furcation. 
Female.—Length 16-19 mm. LHye bare, green, with three diagonal purple 
bands, the lower one considerably wider than the upper two. Frons about three 
and one-half times as high as width at callus, very slightly widened above, yel- 
lowish brown, usually with a darker patch medianly; basal callus dark, shiny 
brown, higher than wide, not touching eyes, and tapering to a slender median 
callus; subeallus rich orange brown, the clypeus and genae grayer, with some 
sparse whitish hair. Antenna uniformly orange, the first two segments with 
black hair; basal portion of third segment rather stout, the dorsal angle with a 
short, forward-projecting process. Second palpal segment rather long and 
slender, orange brown, with short black hair, 
FicgurE 55.—Antenna, front view of head, and palpus of (4) Tabanus acutus and (B) 
T. vicarius. 
Thorax yellowish brown, the dorsum darkest, with five faint, slender, pale 
stripes. Wing pale orange brown, the costal cell and spot at furcation some- 
what darker than rest; cell Rs Somewhat narrowed apically. Legs yellowish 
brown, the tarsi and apex of fore tibia somewhat darker. 
Abdomen, above orange brown, somewhat darker at apex, with a rather 
broad, parallel-sided, pale-yellowish-brown, median stripe the entire length; 
venter nearly uniformly orange brown. 
Male.—Areas of large and small facets of eye sharply differentiated, the 
former extensive, reaching to hind margin and half way down on frontal 
triangle. Second palpal segment with pale hair only, stout, with an acute, de- 
curved apex. Rest of coloration essentially as in female. 
Type—Female, perhaps in British Museum. 
Type locality—North America (New Orleans). 
Distribution.—The Mississippi Delta district at New Orleans and 
below and at mouths of the Apalachicola and Withlacoochee Rivers, 
Fla. May 19 (New Orleans, La.) to August 25 (Johnson’s Bayou, 
La.). In the United States National Museum, 11 females, 2 males. 
TABANUS VICARIUS Walker 
(Fig. 55, B) 
Tabanus costalis Wiedemann, Aussereuropiische zweifliigelige Insekten, v. 1, 
pp. 173-174, 1828; Osten Sacken, Mem. Boston Soc. Nat. Hist. 2 (pt. 4, No. 
4): 450-451, 1876; Hart, Ill. State Lab. Nat. Hist. Bull. 4: 286-2388, 1895; 
Hine, Ohio State Acad. Sci. Spec. Papers 5: 50, 1903; Ohio Nat. 7: 24, 
1906; La. Agr. Expt. Sta. Bull. 93: 46-47, 1907; Philip, Minn. Agr. Eixpt. 
Sta. Tech. Bull. 80: 104-105, 1931; Schwardt, Ark. Agr. Expt. Sta. Bull. 
332: 35-388, 1986. (Preoccupied by Tabanus costalis Lichtenstein.) 
Tabanus vicarius Walker, List of the Specimens of Dipterous Insects in the 
Collection of the British Museum, pt. 1, p. 187, 1848; Stone, Ent. Soc. 
Wash, Proc. 37; 18, 1935. 
