Philonthus sanguinolentus (Gravenhorst, 1802)

This widespread Palaearctic species is generally common throughout Europe although less so in higher northern latitudes, it extends north to the UK and beyond the Arctic Circle in Fennoscandia and east through Asia Minor and Russia to Siberia, it is present along the northern Mediterranean, widespread across North Africa and has recently (2013) been recorded from North America (Ontario). Here it is locally common and often abundant across Wales and southern England north to the Humber although there are very few records from the West Country, further north it is much more local and scarce as far as the Scottish border and beyond this there are only very few and scattered records north to the Highlands and Outer Hebrides. Adults occur year-round and are active over a long season, from February until November or December, and peaking during July and August. Through the winter they may be found under logs or among litter but otherwise they occur among decaying organic matter in a wide range of mostly damp habitats although we have also found them under logs on very dry chalk grassland hillsides in the Chilterns. Adults are powerful fliers and predatory, they may be found among compost and litter and may be common at carrion, during warm weather they fly above dung pasture and may be among the first beetles to arrive at freshly deposited dung, they also occur among horse dung in almost any situation e.g. we often find them among droppings on bridleways in our local woods, a habitat where they are also active at night. Sampling adults is simply a matter of sieving or searching suitable material or setting carrion, dung or pitfall traps but they are very active and difficult to tube when alarmed, especially at carrion or dung where they seem to vanish into the soil or surrounding vegetation.

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​Adults are very distinctive due to the red marks on the elytra, other UK species have red marks to the elytra but the pattern in the present species is distinctive. 6.0-10.0mm (3.7-3.9mm from the mandibles to the elytral apex), entirely black but for two red marks on each elytron, one below the shoulder and one along the suture, these may be united or missing but this is rare, and sometimes the red marks are not obvious but they will if the specimen is manipulated under a powerful light. Appendages pale to dark brown. Head and pronotum with fine and dense transverse and oblique microsculpture forming irregular meshes. Head quadrangular and transverse, about 1.3 times wider than long, with large, weakly convex eyes that are about 1.3X longer than the temples in males and about 1.6X longer in females, median interocular punctures much more widely spaced than each is to the lateral interocular puncture. Anterior margin smoothly rounded, clypeus deeply notched and temples rounded to a broad neck, vertex with scattered large punctures and long stiff setae behind the eyes. Terminal maxillary palpomere longer and thinner than the penultimate segment, antennae with all segments distinctly elongate. Pronotum quadrate or nearly so, broadest towards the base and narrowed to a rounded anterior margin ( viewed from above), posterior angles widely rounded and basal margin smoothly curved, all margins finely bordered, median longitudinal series with five punctures (including one near the apical margin), beyond these scattered punctures to the lateral margins and along the basal margin. Scutellum elongate, triangular and densely punctured and pubescent. Elytra transverse and about as long as the pronotum (measure along the suture), with rounded shoulders and sinuate apical margin, surface finely and densely and pubescent, the pubescence recumbent and overlapping. Abdomen shiny, without microsculpture, basal three tergites with two weakly-curved lines across the base, between these with a double row of fine setiferous punctures on the first tergite and finely and densely punctured on the second and third, tergites otherwise finely and densely punctured and pubescent.  Male eighth sternite deeply emarginate. Basal segment of hind tarsi slender, not noticeably broader than the second, second pro-tarsomere transverse.