The Ohio Naturalist. 
[Vol. V, No. 2, 
238 
Tabanus gilanus Townsend. Whole body dark colored. 
Abdomen with a median longitudinal row of small gray triangles 
and on either side a row of oblique spots of the same color ; other- 
wise black with very narrow gray posterior borders to the seg- 
ments. The red on the sides of the abdomen found in so many 
species is lacking. Wings hyaline without stump on the anterior 
branch of the third vein. P'irst two segments of the antennae 
and base of third red, remainder black. Basal part of third 
antennal segment at widest point about as wide as the length of 
this ])art. In the United States National Museum are some s])ec- 
imens which have been compared with the type by Mr. Coquillett. 
Length 13 to 15 millimeters. 
Tabanus hyalinipennis Hine. The eyes are naked. It has 
the aspect of trimaculatus l)ut is smaller, wings hvaline without 
dark margins to the cross-veins, and with white triangular spots 
on the third and fourth abdominal segments. Length 15 milli- 
meters. Specimens from Oak Creek Canyon, Arizona, taken by 
J. T. Llovd and Dr. F. H. Snow. 
Tabanus illotus Osten Sacken. The wings in this species may 
be said to be subhyaline, especially on the anterior part. Faint 
clouds on the cross- veins and furcation of the third vein. Anten- 
nae with the third segment rather broad and reddish at the base. 
Basal annulus almost as broad as long, distinctly excised and 
with a well marked upper angle ; apical portion black and dis- 
tinctly shorter than the basal annulus. Legs black, somewhat 
lighter at bases of all the tibia. Length 12 to 14 millimeters. 
A northern species taken in Alaska and the Hudson Bay region. 
Tabanus insuetus Osten Sacken. This appears to be a varia- 
l)le species. The size of the head and width of the front are 
variable; some specimens have a long stumj) on the anterior 
branch of the third vein, while in others there is no vestige of it. 
(Jther parts are variable and it would seem that more than one 
species is included under the name, but constant characters for 
separation appear to be lacking. As it now stands insuetus is 
separated from all western species l)y the presence of a single 
narrow brown stripe across the eye. This shows almost as well 
in drv as in living specimens. Length about 12 millimeters. 
Known from Alaska, British Columbia, Washington, Wyoming, 
Colorado, California, Nevada and Utah. 
Tabanus intensivus Townsend. When Townsend described 
this species he compared it with gilanus which appears to be its 
nearest relative. The general color of the whole body is black 
clothed with grav pile. The abdomen has a median row of tri- 
angles, on each side of which is a row of oblique spots; wings 
hvaline with no stump on anterior Ijranch of third vein. The 
antennas are usually black but the hrst and second segments and 
even the base of the third may be obscure reddish. The third seg- 
