Tabanus autumnalis, the large marsh horsefly, is a medium-sized species of biting horse-fly. It is somewhat scarce compared to T. bromius and T. bovinus. This species shows slightly more of a preference for coastal marsh than some of the other European Tabanus, sometime even found in saltmashes. Description Eyes without coloured bands. Male: postocular edge almost covered by the eyes and with a short fringe. Palps: second segment oval. Female: postocular edge narrower; interocular 4-5-6 times longer than wide; median plate bare, joining the lower one. Antennae: third segment with a blunt or short tooth. Wing has a hyaline costal cell.Abdomen: dorsal side with a lateral line of light spots placed between the midline and the lateral edge of the tergites, so that on the black background you can see five light longitudinal lines: one median, two lateral, and two marginal, separated from each other by four black lines.Seguy, E. 1927 Faune de France 13: Diptères (Brachycères) (Stratiomyiidæ, Erianidæ, Cænomyiidæ, Rhagionidæ, Tabanidæ, Codidæ, Nemestrinidæ, Mydaidæ, Romoyiidæ, Therevidæ, Omphralidæ) Lechevalier editions (Paris: Éditions Faune de France) Wing length is 13–16 mm and about 16–22 mm in body length.
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