Tachinus proximus Kraatz, 1855

This widespread Western Palaearctic species is locally common across Europe from the Pyrenees to the Black Sea in the south and to the north, where it is much more local and sporadic, it extends to the UK and the far north of Fennoscandia, the eastern limit of the distribution is North West Russia, and it is sometimes quoted as occurring in North America but this probably refers to another species. In the UK it occurs throughout England, Wales and Scotland and there are records from Orkney and the north of Ireland but it is very local and generally scarce, it extends to higher mountain altitudes in Wales and the Scottish Highlands, and has been recorded up to 2300 m in the Alps. Adults are present year-round; they overwinter among decaying organic matter and are active from March until late in the autumn, peaking in abundance during August and September. The species is often associated with herbivore dung but it prefers shady situations, often in woodlands, and rarely occurs on open dung pasture, it otherwise occurs among carrion and compost etc. and is sometimes common in large decaying fungi in the autumn. Little is known of the biology but the species is probably a spring breeder with new generation adults aestivating and appearing from late summer, adults are predatory, mostly nocturnal and often occur in numbers. Pitfall trapping and sieving likely material are the best sampling methods and adults are likely to appear among extraction samples at any time of year.

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4.5-8.0mm.  Body elongate and fusiform with a distinctly tapering abdomen, forebody shiny and glabrous, head black, pronotum black with broad brown lateral margins and narrow brown basal and apical margins, elytra dark brown or reddish-brown with the disc extensively darkened, abdomen black to dark brown, or with the tergites paler around the margins, legs brown, antennae dark with three or four basal segments paler, palps extensively dark, sometimes entirely black. Head smoothly convex and without structure between convex and protruding eyes, temples long and converging but normally concealed within the thorax, antennae inserted outside the base of the mandibles, 11-segmented and filiform. Pronotum transverse, broadest behind the middle and evenly curved to rounded posterior angles and slightly protruding anterior angles, surface smoothly convex and without structure, very finely punctured and microsculptured. Scutellum large, triangular and punctured and microsculptured as the pronotum. Elytra elongate and almost parallel-sided from rounded shoulders to separately-rounded apical margins, surface very finely punctured and reticulate, somewhat dull and contrasting with the shiny pronotum, without striae although sometimes with obscure longitudinal depressions. Abdomen finely reticulate throughout and somewhat dull, lateral margins strongly bordered and with several long setae on the fifth and sixth visible segments, the sixth segment characteristically shaped in the female and the aedeagus distinctive in the male. Legs long and slender; all tibiae with long bristles and all tarsi 5–segmented and simple.