Dec., 1904.] 
Tabanidae. 
231 
the antennae, otherwise the face including the cheeks, and the 
front below to above the frontal callosity denuded and shining 
black; above the frontal callosity and connected with it by a 
narrow interval is a nearly rectangular shining black spot, other- 
wise the front is covered with dark gray pollen. No ocelli. The 
third segment of the antenna appears slightly reddish caused it 
seems b\- a covering of grayish pollen, slightly enlarged at base 
but not with a distinct basal process, basal annulus as long or a 
little longer than the other four taken together; second segment 
small with a few black hairs at the anterior upper angle; first 
segment of normal form above but strongly produced below 
making it appear almost as though the second segment is at- 
tached to its side, furnished above and below with short black 
hairs ; legs black ,all of the tibiae enlarged but not so much as in 
Lepidoselaga lepidota, hind pair with a dense row of cilia on the 
outer side. Wings black with the exception of apexes of the first 
and second submarginal cells which are clear hyaline. The line 
of union of this hyaline and the black forms a strong curve, and 
at no point is the hyaline wider than the fourth of the total length 
of the second submarginal cell. Abdomen uniform blue-black 
above and beloAv. Length 13 millimeters. 
A female taken in Oak Creek Canyon, Arizona, in August, 
1904, by Dr. F. H. Snow for whom the genus is named. 
The insect has affinities with both the genera Selasoma and 
Bolbodimyia but does not fall in either. It is an interesting 
species and a splendid addition to the known North American 
fauna. 
H.em.\topota Meigen. 
A genus of nearly fifty species widely distributed in the 
Eastern Hemisphere but represented by only two speices in the 
Americas. The peculiarly enlarged first antennal segment and 
the wide transverse front are characteristic. 
Haematopota americana Osten Sacken. The two known 
American species are both found in the United States, but only 
this one is western. It is larger than punctulata of the eastern 
states, and in the specimens before me the third antennal seg- 
ment, although somewhat compressed in both, is wider and 
shorter in punctulata. Osten Sacken states that americana is 
closely related to pluvialis of Europe and has published his results 
of a comparison of the two. There are onlv a few specimens of 
punctulata in collections so the opportunity for a eareful com- 
parison of our two species has not appeared. 
T.\b.\nus Linne. 
Some authors have considered the species here included under 
this one genus as belonging to three genera. The species with 
