105. 
106. (103) 
107. 
108. (106) 
109. 
110. 
111. (108) 
112. 
113. 
114. 
115. (111) 
116. (102) 
117. 
HORSEFLIES OF THE SUBFAMILY TABANINAE 
Key to Nearctic Females of Tabanus—Continued 
Length 17 mm or less; second palpal segment slender to stout; 
GusuaillitvseaSterm)) peste ter 2 ee 
Second palpal segment distinctly swollen basally; frons about 
five times as high as width at base 
epistates Osten Sacken, p. 136. 
Second papal segment slender throughout; frons about three 
and one-half times as high as width at base 
aurilimbus, new species, p. 130. 
Second palpal segment unusually slender______________________ 
Second palpal segment not unusually slender____________-_-__ 
Median black stripe of abdomen narrow; dorsal angle of third 
antennal segment obtuse; orange on side of first tergite 
reaching to anterior margin; second sternite entirely orange 
trepidus MeDunnough, p. 131. 
Median black stripe of abdomen broad; dorsal angle of third 
antennal segment small, usually acute, the dorsal excision 
pronounced ; first tergite usually darkened along entire an- 
terior margin; second sternite usually blackened medianly 
gracilipalpis Hine, p. 182. 
Antenna black, rarely with a little orange on second and base 
of third segments; third segment narrow, with obtuse dorsal 
angle and little if any dorsal excision; palpus strongly 
swollen basally; vein R, often with a stump_____-____-___- 
Nothwithathis combination of ,charactersi 2 i2.- 2225 
Frons slightly iess than three times as high as wide, the sides 
MEAT. DAbAaAlel. 2222 tate philipi, new species, p. 1338. 
Frons about four times as high as width at base, usually some- 
wham OITCC 12D ON CS ae 1 ope on rays ee eo Pee 
Venter of abdomen with mostly yellowish hair, although there 
may be some scattered black hairs medianly 
sonomensis Osten Sacken, p. 133. 
Venter of abdomen nearly uniformly clothed with fine black 
hair, the yellowish hair usually sparse except along incisures 
sonomensis var. phaenops Osten Sacken, p. 134. 
SUMGa NT SRNO LIMO SC te oe Be ee ae Ee A 
SHUG aula CmiGde Gas fa woe 3 ee 
Pale spots on median black area of abdomen forming a slender, 
usually continuous line; third antennal segment largely 
black ; length 12-18 mm; (Atlantic Coast) 
daeckeit Hine, p. 135. 
INGimenDInehywaSnaDOVeE! os een 
Frons about five times as high as width at base, somewhat 
widened above; antenna largely orange; 16 mm or less in 
length; palpus stout basally__epistates Osten Sacken, p. 136. 
Frons not over four times as high as width at base, and dis- 
agreeing in one or more of the other characters mentioned 
BM ON oe TE gee ae eer Sr eyes 2 ae 
Dorsal excision of third antennal segment shallow; second palpal 
segment creamy white and somewhat swollen basally; frons 
broad and distinctly widened above 
haemaphorus McDunnough, p. 137. 
Dorsal excision of third antennal segment rather pronounced ; 
second palpal segment orange brown and scarcely swollen 
basally; frons neither so broad nor so widened above 
affinis Kirby, p. 1387. 
Second palpal segment strongly swollen basally, pale cream col- 
ored; basal callus flat, wrinkled_nudus McDunnough, p. 1388. 
Second palpal segment moderate in width at base, brownish ; 
basalseallus: convex = 2) = a2 Lee captonis Marten, p. 139. 
Abdomen with bands along posterior margins of tergites; little 
or no indication of median or sublateral spots__________-____ 
Abdomen entirely dark, or distinct median or sublateral pale 
Spots,vor boths,presente 2-2. h ee et 
Palpus short, stout, creamy white____oklahomensis Stone, p. 140. 
Palpusyslenders reddish brown’ to black2_-2_--=- == = eee 
45 
105 
107 
108 
109 
gE 
110 
112 
115 
113 
