HORSEFLIES OF THE SUBFAMILY TABANINAE 131 
Abdomen above orange brown; tergite 1 medianly, a narrow median stripe 
on anterior half of tergite 2, tergite 4 medianly, and most of tergites 5-7 black- 
ish; rather distinct, yellowish-brown, median triangles and sublateral spots on 
tergites 2-5 or 6, the median triangles rather broader than in other of the 
orange-sided species; sublateral spots with inner margins parallel, outer mar- 
gins oblique and reaching to lateral margins; venter yellow orange, with con- 
colorous hair, sometimes blackened apically and in a narrow median stripe. 
Male.—Unknown. 
Type.—Female, Boston Society of Natural History. Four para- 
types, collections of Graham Fairchild and of the United States 
National Museum (No. 51970). 
Type locality.—Paris, Maine. 
The type was collected by C. F. Frost, July 14, 1936. The para- 
types were collected at Northboro, Mass., July 5, 1936, by C. F. 
Frost; at Reading, Mass., June 29, 1933; and at Rock, Mass. 
FIcuRE 62.—Antenna, front view of head, and palpus of (A) Tabanus aurilimbus and 
B) T. trepidus. 
This species is close to trepidus McDunnough, but in trepidus the 
palpus is clothed with black hair and is even more slender and taper- 
ing, the antenna has a shallower dorsal excision, there is more black 
on the abdomen, and the hind tibial fringe is black. 
TABANUS TREPIDUS McDunnough 
(Fig. 62, B) 
Tabanus trepidus McDunnough, Canad. Ent. 53: 142, 1921; Stone, Ann. Ent. 
Soe. Amer. 23: 301-3802, 1980; Philip, Minn. Agr. Expt. Sta. Tech. Bull. 
80; 117, 1931. 
Rather small, stout; abdomen with orange sides; subcallus pollinose; palpus 
unusually slender; basal portion of third antennal segment with strong dorsal 
angle but almost no excision. 
Female.—Length 18-15 mm. Eye pilose, deep purple, with four green bands. 
Frons gray tinged with yellowish brown, about three and one-half times as 
high as basal width, widened above; basal callus shiny dark brown to black, 
subquadrate, usually with a dorsal notch and not quite touching eyes; median 
eallus black, slender, usually narrowly joined to basal callus; ocellar tubercle 
orange brown; subcallus, clypeus, and genae yellowish gray, the hair yellowish. 
Antenna orange, the first two segments and annuli sometimes blackish; 
dorsal angle of third segment prominent, the width of basal portion being 
only slightly less than the length; dorsal excision very shallow; annulate por- 
tion shorter than basal portion. Second palpal segment unusually slender, 
orange brown. 
Thorax dark brown to black, with faint lines of lighter pollen above; 
prescutal lobe usually orange; hair of pleura mixed yellow and black. Wing 
hyaline, the costal cell and anterior portion of wing tinged with brown. Legs 
black, the fore tibia tinged with brown, the middle and hind tibiae orange 
brown; hind tibial fringe black. 
Abdomen orange brown, with a black median stripe widening apically; 
faint yellowish sublateral spots and a yellowish median spot at posterior 
margins of segments 1-4; venter yellowish brown. 
