TABANID^ OF OHIO. 55 



Female: Front with parallel sides, frontal callosity shining brown, 

 not quite as wide as the front, nearly square and with a linear prolon- 

 gation above. Segments of the abdomen above with prominent gray, 

 hind margins which expand into large gray triangles in the middle ; 

 usually a black mark on the anterior part of each of the second and third 

 segments at the apex of the gray triangle. 



Male : The division between the large and small facets of the eye 

 prominent; head slightly more convex than in the female but nearly of 

 the same size, coloration of the whole body the same as in the female. 



Habitat: Common in all parts of Ohio in August. 



This species is very near extil and ahdominalis, neither of 

 which have been recoznized from this state, although it it within 

 their range. The large, gray, abdominal triangles are characteristic 

 of sulcifrons. In abdominalis the first posterior cell is closed, and 

 the front in the female is noticeably narrowed. In exul the head 

 of the male is sub-hemispherical and the abdominal triangles are 

 moderate. Regarding its relationship with variegatus see under 

 that species below. 



In certain parts of Ohio this species is so abundant that it is 

 one of the worst of stock pests. 



TABANus suPERjuMENTARius Whitney. 



Length 16-20 mm. This species resembles trimaculatus in many 

 respects but the following differences may, be noted : the legs are uniformly 

 black or at least dark with occasionally a suggestion of reddish at the 

 bases of the tibiae ; the wings are uniformly subhyaline with no darker 

 margins to the cross veins and bifurcation of the third vein; dorsally, 

 abdominal segments two, three, four and five each with a very small 

 white triangle in connection with the middle of the posterior margin ; 

 ventrally, there is not the contrast between the colors of the median and 

 lateral areas exhibited in trimaculatus. 



The male and female are colored alike except in the specimens before 

 me the thorax is not so distinctly white in the former as in the latter. 



Habitat : Akron and Cincinnati. 



TABANUS TRIMACULATUS Palisot dc Bcauvois. 



Length 16-19 mm. Antennae dark, nearly black, palpi yellowish; 

 thorax dorsally with whitish "pollinose stripes and brownish intervals, 

 scutellum uniformly whitish pollinose; legs black except base of all the 

 tibiae which are white; wings hyaline, costal cell brown, bifurcation of 

 the third vein, cross veins and sections of veins that have a transverse 

 direction rhargined with brown ; abdomen dorsally black with a large 

 white triangle in connection with the middle of the posterior margin of 

 each of segments three, four and five; abdomen ventrally white on the 

 sides and a wide black median stripe. 



The male and female differ only in sexual characteristics. 



Habitat : All sections of the state during the latter part of 

 May and the first half of June. Occasionally as late as July first. 



The three prominent triangular white markings of the ab- 

 domen easily distinguish this species. 



