138 MISC. PUBLICATION 305, U. S. DEPT. OF AGRICULTURE 
ing eyes; median callus black, spindle shaped, about one-third width of frons 
and usually connected with basal callus; ocellar tubercle well defined, dark 
reddish, situated at apex of a black triangle, the base of which rests on 
hind margin of vertex; subcallus, clypeus, and genae yellowish gray, the 
clypeus and genae with concolorous hair. First two antennal segments dark 
orange or black, with black hair; third dark orange at base, the annulate portion 
black, the transition gradual; basal portion with a strong dorsal angle and 
excision; annulate portion about equal to greatest width of basal portion. 
Second papal segment rather slender, dark orange, with short black hair. 
Mesonotum black, with faint yellowish lines; prescutal lobe usually more 
or less orange. Pleura, sternum, and coxae dark gray, with mostly yellow- 
ish-gray pile. Wing nearly hyaline, the costal cell and region of central cross 
veins brownish and a faint spot at furcation. Legs black, the middle and 
hind tibiae and tarsi, and base of fore tibia, largely dark orange; hind tibial 
fringe prominent, black. 
Abdomen above black, the sides of tergites 1-8 or 14 more or less deep orange, 
leaving a broad, black, median stripe on these segments; this orange may 
extend across fourth tergite onto fifth, or the fourth may be almost entirely 
black; often oblique yellow spots on orange of tergites 2-3; hind margins of 
tergites with narrow pale borders which widen slightly medianly to form wide, 
FIGURE 66.—Antenna, front view of head, and palpus of (A) Tabanus affinis and (B) 
. MUaUS. 
but short, pale-yellowish triangles; venter deep orange, darker apically and on 
center of sternites 1-2, with pale-yellowish posterior fringes on sternites. 
Male.—EKye densely pilose, with facets of uniformly small size; second palpal 
segment about twice as long as its greatest width, blunt at apex. Dorsal black 
stripe of abdomen considerably narrower than in female, interrupted by 
median yellow spots on segments 2-3; black of venter confined to last three 
sternites. 
Type—sSex and collection unknown. 
Type. locality —Latitude 65°, Canada. 
Distribution —Northern North America from Alaska to Newfound- 
land south to Arizona and Connecticut. June 13 (Anchorage, 
Alaska) to August 17 (Rigolette, Newfoundland). In the United 
States National Museum, 64 females, 15 males. 
Osten Sacken and Hine both examined the type of Zabanus triliga- 
tus Walker and established the synonymy. Specimens sent to the 
British Museum by Philip were also compared with the type by 
Austen and declared to be the same. Walker’s description is very 
misleading, particularly as to size. A number of males were found by 
the writer hovering on top of Bear Mountain in Connecticut (2,354 
feet altitude) around 10 a. m., July 26, 1934. 
TABANUS NUDUS McDunnough 
(Fig. 66, B) 
Tabanus nudus McDunnough, Canad. Ent. 53: 148, 1921; Hine, Canad. Ent. 55: 
144, 1923; Philip, Minn. Agr. Expt. Sta. Tech. Bull. 80: 112-113, 1931. 
Medium sized; blackish brown, the orange on side of abdomen reaching 
across first tergite ; wing not distinctly spotted ; subcallus denuded; second 
