238 The Ohio Naturalist. [Vol. V, No. 2, 



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. First 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 part. In the United States National Museum are some spec- 

 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 trimaculattis but is smaller, wings hyaline 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 Canvon, Arizona, taken bv 

 J. T. Llovd and Dr. F. H. Snow. 



Tabanus illotus Osten Sacken. The wings in this species may 

 be said to be subhy aline, especially on the anterior part. Faint 

 clouds on the cross- veins and furcation of the third vein. Anten- 

 UcE 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- 

 ble species. The size of the head and width of the front are 

 variable ; some specimens have a long stump on the anterior 

 branch of the third vein, while in others there is no vestige of it. 

 Other 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 by 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 gray pile. The abdomen has a median row of tri- 

 angles, on each side of which is a row of oblique s])ots; wings 

 hyaline with no stump on anterior branch of third vein. The 

 antennae are usually black but the first and second segments and 

 even the base of the third mav be obscure reddish. The third seg- 



