38 MISC. PUBLICATION 305, U. S. DEPT. OF AGRICULTURE 
Zeller, which differs in lacking an ocellar tubercle and in being more 
hairy throughout. The two chief characters of Szladynus, possession 
of pilose eyes and an ocellar tubercle, unfortunately do not always oc- 
cur together. 7. cinctus and 7’. carolinensis lack pile on the eye 1n the 
female and yet have very distinct ocellar tubercles. Certain south- 
western species such as 7’. gilanus and 7’. intensivus have pilose eyes 
but no ocellar tubercle and yet appear closely related to species such 
as 7. laticornis in which the ocellar tubercle is well developed. 
Because of these anomalous species that fit into neither Zabanus 
restricted nor Sziladynus, and yet show no other characters to justify 
the erection of more genera, the writer has preferred to leave the 
further division of 7'abanus until more satisfactory characters can 
be found. 
Key to Nearctic Females of Tabanus 
it: Eye pilose; second palpal segment very slender; no distinct ocel- 
lar tubercle ; abdomen with a median stripe and rounded sub- 
lateral. SpOUS 2525220 43.2 a ee eee ore eee 2 
If eye is pilose and second palpal segment is very slender, a pro- 
nounced ocellar tubercle is present and abdomen is other- 
Wise Marked 2.2.43 See a Ee ARE ad bee es Ate coder 4 
2. Abdomen dark brown, with median line narrow and widening on 
each tergite at posterior. Margin= =< 22.2222 ee es a 
Abdomen somewhat orange laterally, with a rather broad, nearly 
parallel-sided, median line______--_____ bishoppi Stone, p. 53. 
3. Frons about two and one-half times as high as wide, the basal 
callus transverse; base of third antennal segment rather 
Slender OS Fee et er a quaesitus, new species, p. 54. 
Frons about four times as high as wide, the basal callus higher 
than wide; base of third antennal segment rather stout 
exilipalpis, new species, p. 54. 
4. (1) Abdomen above with both median and sublateral pale spots; 
those of median row may be contiguous but do not form a 
parallel-sided stripe; no distinct ocellar tubercle present____-_ D 
Abdomen otherwise marked or a distinct ocellar tubercle present_ 38 
5. Fureation without a distinets brown spotoia2=- 2-2 a ee ee ee 6 
Fureation with-a distinct brown:spota2 23 S22 es ei 33 
6. Dorsum of thorax decidedly yellow in color, without longitudinal 
stripes; median abdominal triangles forming a conspicuous, 
continuous line regularly widening posteriorly on each ter- 
vite: frons narrow, widened above 222-2422 ee eee i 
Without this combination: o£ characters. #22535 ee es 8 
6 Third antennal segment with annulate portion black; femora 
lareelyionra yi sat ete eee fulvulus Wiedemann, p. 55. 
Third antennal segment entirely orange; femora entirely yellow- 
DES} 6 Nee ba ea ee coy fulvulus variety pallidescens Philip, p. 56. 
8. (6) Median gray spot on tergite 2 lacking or much smaller than large 
ones on tergites 3 and 4______________ dorsifer Walker, p. 56. 
Median spots on tergites 3 and 4 not markedly larger than that on 
TereiterD 2 hoa se ea ee 9 
9. Hye ‘piloseso 2 to Ee a LE Be eek 10 
Hye ‘bares tee eee ee et cero eae eee Pee eee 15 
10. Basal portion of third antennal segment about as wide as long, 
usually entirely orange, contrasting with black annulate 
portion; first antennal segment not greatly enlarged above; 
side of first tergite orange its entire length 
laticornis Hine, p. 57. 
Basal portion of third antennal segment obviously longer than 
wide; either first antennal segment greatly enlarged above 
or abdomen not -broadly.orange laterally] 2222" === es 11 
11. First antennal segment strongly swollen above 
erythraeus (Bigot), p. 58. 
First antennal segment not strongly swollen above_—-~-~---~-- 
