HORSEFLIES OF THE SUBFAMILY TABANINAE v4 
Basal portion of third antennal segment with or without a prominent 
dorsal angle, but if this is produced forward the eye is bare_____ 6 
6. Basal callus in female lacking or very much reduced, separated from 
eye by a considerable space; neither palpus black nor abdomen 
Wilthea “Marrow GOLSALAStCIpe ses * aie tre ke eee Le aie ey 7 
Basal callus in female as wide, or nearly as wide, as frons, or, if 
narrowed, still considerably wider than median callus; either 
palpus black or abdomen with a narrow dorsal stripe__.._______ 9 
7. Eye distinctly pilose; no distinct ocellar tubercle (eye of female 
usually with a single, diagonal, purple line which often shows even 
in dried specimens), ~_---_____----_- Atylotus Osten Sacken, p. 19. 
Eye bare or very sparsely pilose; ocellar tubercie present or absent 
(frons of female about five times as high as width at base) ~~ 8 
8. Basal callus a swelling at base of a slender raised ridge; a distinct 
ocellar tubercle present in female; abdomen brownish, with white 
bands, the apex compressed__.__----____ Leucotabanus Lutz, p. 24. 
No basal or median calli or ocellar tubercle present; bright green 
or yellow species, the abdomen not distinctly compressed 
PB OS CCE Ty > oe a Chlorotabanus Lutz, p. 27. 
9. Annulate portion of third antennal segment hairy; no ocellar tubercle ; 
second palpal segment short and stout, with erect hair; pro- 
I OSCIS RS NOT eres Ee Anacimas Enderlein, p. 28. 
Not agreeing entirely with above, the hair of third antennal segment 
VEbVaAMNecOnspDICUOUSe EE present2-22 _-.--_- 2 10 
10. Rather small species with bare or sparsely pilose eye, scarcely any 
angle, and no dorsal excision on third antennal segment, and 
frequently a stump vein from vein Ri___Stenotabanus Lutz, p. 31. 
Hye bare or pilose, but if a stump vein from vein R: is present either 
the dorsal angle of the third antennal segment is distinct or the 
evenssaensely pilose, or both_-_—~_______ Tabanus Linnaeus, p. 36. 
Some difficulty may be experienced in properly placing males in 
this key, but a little acquaintance with the habitus of the different 
genera will usually prevent misdetermination. 
The Genus HAEMATOPOTA Meigen 
Chrysozona Meigen, Nouvelle classification des mouches 4 deux ailes, p. 23, 1800. 
(Genotype, Tabanus pluvialis Linnaeus.) 
Haematopota Meigen, Illiger’s Mag. f. Instektenkunde 2: 267, 1803; System- 
atische Beschreibung der bekannten europaischen zweifliigeligen Insekten, 
v. 2, p. 78, 1820; Johnson, Psyche 19: 181-188, 1912. (Genotype, Tabanus 
pluvialis Linnaeus. ) 
Generic characters.—Small, slender, grayish species; eye somewhat pilose; 
frons very broad and basal callus transverse; first antennal segment one and 
one-half to three times as long as wide and usually swollen; third with four 
divisions, the first division with no distinct angle above; wing brown or gray, 
with hyaline maculations. 
Since the status of the names published by Meigen (12) in 1800 is 
still unsettled, with strong arguments both for and against their use, 
the writer has preferred to use the name Haematopota, as has been 
customary in this country. 
Key to the Nearctic Species of Haematopota 
1. Knob of haltere white or pale yellow____americana Osten Sacken, p. 8. 
Knobrorshaltere, @ark brown 2022) 2) a es a 2 
2. Front tibia distinctly swollen; basal portion of third antennal segment 
less than twice as long as greatest width_punctulata Macquart, p. 9. 
Front tibia not swollen; basal portion of third antennal segment more 
than twice as long as greatest width-_--__-_~- rara Johnson, p. 10. 
