Tabanus gracilis

Females can be recognized by the brown color, abdominal pattern, wing veins faintly margined with brown, and the shape of the calli on the face. Females: eyes bare; abdomen with median and sublateral pale spots or triangles; abdomen with neither a parallel-sided median stripe nor median pale triangles not forming an impression of a serrated stripe; fork of veins R4+5 without a dark spot; mesonotum not covered with yellow or golden hair; length usually over 12 mm; frons parallel-sided or only slightly widened above; subcallus not shiny; wing with cell R5 not narrowed or closed at margin; scape of antennae not noticeably swollen dorsally; antennae uniformly orange; wing membrane hyaline or grayish-blue with the veins very faintly margined with light brown; basal and median calli large, shiny, yellowish-brown, and broadly joined. Males: eyes bare; abdomen with pale median and sublateral pale spots or triangles, median pale triangles not forming a parallel-sided stripe; yellowish or brownish species usually more than 12 mm in length; costal cell hyaline or tinged with yellow; eyes with large and small ommatidia distinctly differentiated; sublateral abdominal spots small, pale brown, rarely reaching anterior margin of tergites; mesonotum with brown hairs. one of the most abundant species in se US With known pathogenic transmission of Anaplasma marginale , a bacteria that affects cattle.