HORSEFLIES OF THE SUBFAMILY TABANINAE 139 
palpal segment strongly swollen at base, pale cream colored; basal callus flat 
and somewhat wrinkled. 
Female.—Length 14-17 mm. Eye densely pilose, green, with three diagonal 
purple bands. Frons yellow brown, paler just above basal callus, a little less 
than four times as high as width at base and distinctly widened above; basal 
callus orange brown, square or transverse, nearly touching eyes, and usually 
flat and wrinkled; median callus elongate, black, often narrowly connected with 
basal callus and the distinct, orange-brown, ocellar tubercle; subcallus denuded, 
flat, shiny orange brown, often nearly black on sides. First two antennal 
segments yellowish, with black hair; third orange, somewhat darkened above 
beyond dorsal angle, the annulate portion nearly black; basal portion stout, 
nearly as broad as long, the dorsal angle prominent, dorsal excision moderate; 
annulate portion shorter than width of basal portion. Clypeus and genae pale 
gray, often tinged with orange above palpi and with dense cream-colored hair. 
Second palpal segment short, very stout at base, tapering to an acute apex, 
cream colored, with concolorous and often scattered black hair. 
Mesonotum dark brownish black, with rather distinct stripes of yellowish- 
brown hair; prescutal lobe orange, with black hair. Pleura, sternum, and 
coxae gray, with white hair, the mesopleurite tinged with orange and with 
some black hair. Wing hyaline, the costal cell, margins of veins in basal 
portion of wing, and furcation faintly tinged with grayish brown; venation 
normal. Femora gray, the apices of at least the middle femur orange; tibia 
orange brown, the fore tibia distinctly darkened apically; hind tibial fringe 
black or black mixed with yellow; tarsi orange brown to black, the fore pair 
darkest. 
Abdomen above orange brown, with a black median stripe, widening apically ; 
a median row of small yellowish triangles and rather distinct, oblique, yellow- 
ish, Sublateral spots on tergites 2-4 or 2-5; venter orange brown, darkened 
apically, with dull-yellowish posterior bands. 
Male.—Hye facets almost uniformly small; frontal triangle with gray pollen. 
Outer claw of fore tarsus considerably longer than inner claw. Body colora- 
tion as in female, the orange on abdomen usually more extensive. 
T'ype.—Kemale, Canadian National Collection, Ottawa. Paratypes, 
Canadian National Collection; three paratypes, Museum of Com- 
parative Zoology. 
Type locality —Ottawa, Canada. 
Distribution.—Alaska and Maine to Wyoming and Massachusetts. 
May 26 (Lanoraie, Quebec) to July 15 (Banff, Alberta). In the 
United States National Museum, 37 females, 4 males. 
TABANUS CAPTONIS Marten 
(Fig. 67, A) 
Tabanus recedens Walker, List of the Specimens of Dipterous Insects in the 
Collection of the British Museum, pt. 5, sup. 1, p. 201, 1854. (Preoccu- 
pied by Tabanus recedens Walker, 1848.) 
Tabanus captonis Marten, Canad. Ent. 14: 211, 1882; Hine, Ohio Nat. 5: 235, 
1904; McDunnough, Canad. Ent. 53: 141-142, 1921. 
Tabanus comastes Williston, Kans. Acad. Sci. Trans. 10: 137-138, 1887. 
Medium sized; orange brown, with orange on side of abdomen reaching to 
anterior margin of first tergite, third antennal segment stout, with a distinct 
dorsal angle; subecallus denuded; palpus brownish, not greatly swollen. 
Female.—Length 14-17 mm. Hye with dense, short pile, deep purple, with 
four diagonal green-blue bands. Frons yellowish brown, about three and one- 
half times as high as width at base, decidedly widened above; basal callus 
orange brown to black, subquadrate, not touching eyes and distinctly convex 
in profile; median callus rather short and stout, black, separated from, or 
narrowly joined to, basal callus and usually with a median longitudinal de- 
pression; vertex with a rounded, reddish-brown, shiny spot, not touching eyes, 
in middle of which lies a distinct ocellar tubercle of same color; hair of vertex 
and frons black; subeallus dark yellowish brown, with black hair. First two 
antennal segments yellowish brown, with black hair; third orange, the annulate 
portion black and basal portion sometimes darkened apically; basal portion 
