HABITS AND LIFE HISTORIES OF TABANID^. 



23 



dimensions. These streams are fed by small springs and therefore 

 contain water the year round, forming in their beds pools and riffles 

 over which the sexes of suleif7'ons ma}" be seen flying much of the 

 time. 



I am not fully prepared to say why this particular species is so 

 abundant in these counties and entirely absent in other counties of 

 the same latitude in the western part of the same State; but it appears 

 that there is present some condition which is necessary to its success- 

 ful existence. The statement maj^ be made in this connection that 

 the autumn horsefly appears to prefer high ground, such as described, 



Fig. 2.—Tabanus i<ulcijnjii!<: a, iemale; b, male; c, terminal abdominal teeth of pupa; 

 D, pupa. All enlarged (original). 



to low bottom land where many other horseflies And conditions exactly 

 to their liking. 



The adult (fig. 2, a, b) is a large brown fly 18 to 21 mm. in length. Palpi brown- 

 ish, antennie nearly blaek, with each third segment brownish at the base; legs dark, 

 bases of the tibite lighter, the front pair black with the exception of the bases of the 

 tibi;e and therefore much darker in general coloration than the others; wings with 

 a distinct brownish tinge, cross-veins at the end of the discal cell, and the furcation 

 of the third vein plainly margined with dark brown, first posterior cell open. 



Female: Front of moderate Avidth, sides parallel, frontal callosity shining brown, 

 not quite as wide as the front, nearly square and with a linear prolongation above. 

 Segments of the abdomen above with prominent, gray hind margins which expand 

 into large gray triangles at the middle; usually a black marking on the anterior 

 part of each of the second and third segments at the apex of the gray triangle. 



Male: Division between the large and small facets of the eye prominent; head 

 somewhat more conve.x; than in the female, but of nearly the same size. Coloration 

 in its entirety as in the other sex. 

 3619— No. 12, pt 2—06 2 



