Bryoporus cernuus (Gravenhorst, 1806)

This species is widespread across Central and Northern Europe and western Russia, becoming more common from west to east, to the south it occurs mostly in cooler mountain regions from the Pyrenees and the Alps to Bulgaria but it seems to be largely absent from the Balkan Peninsula. To the north it is very local and rare in Germany, Denmark and Poland and rather less so throughout Fennoscandia where it extends well beyond the Arctic Circle. Beyond this there are scattered records from the eastern Palaearctic region. There are only a few records from the UK, all from southern and central England, the present status is not understood and Joy, in his 1932 handbook, noted the species as England south to Leicester. Irel. U.; vr., but the Irish record is very doubtful and almost certainly in error. Typical habitats in Northern Europe are areas of permanently damp woodland with plenty of trees in various stages of decay; here adult beetles occur among litter and moss and in decaying fallen wood. They have been recorded throughout the year but most records seem to be from April (Poland) or June and September (Finland). In the UK adults have occurred in Heathland and fens, most records are very old, pre 1967, but it was found In Sutton Fen in April 2016. Nothing is known of the biology.

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Large, 5-7 mm, fusiform and weakly convex, forebody and elytra glabrous and shiny, abdomen finely pubescent, head black, pronotum black or obscurely reddish about the posterior angles, elytra red or with the scutellary area and lateral margins darkened, abdomen dark with the apical margins and several apical tergites red (varies.) Antennae dark with three, and sometimes the base of the fourth, pale basal segments, mouthparts and legs pale reddish or brown. The extent of the pale colour to the pronotum varies, and in var merdarius Ol, it is entirely red. The species may be identified by the following combination of characters: Antennae gradually thickened from the fourth segment, the third segment slightly longer than the second and segments 8-10 weakly transverse. Terminal maxillary palpomere elongate and, across the base, only slightly narrower than the penultimate segment. Head with a strong setiferous puncture beside the inner margin of each eye. Pronotum very finely and rather densely punctured. Elytral almost parallel-sided, with the sutural margin raised and three rows of fine punctures from the base. Ventral surface of middle and hind tarsomeres finely pubescent, without isolated larger setae.