This is a locally common species of lowland forests throughout the Palaearctic region, from Portugal east through temperate Asia to Japan and from Mediterranean North Africa north to southern Scandinavia and the UK. Adults occur beneath dead or damaged bark of a very wide range of deciduous and, much less frequently, coniferous trees; they generally frequent close-fitting and moist bark but may persist as this becomes dry and loose. They are present year-round and often in numbers, during the winter under damp or even waterlogged bark on logs or fallen timber, and through the spring and summer often under dry or powdery bark, two peaks in abundance occur; the largest from April to June and a smaller one from October to December. The typical habitat is open woodland with plenty of fallen and decaying timber but they may also be found in sparsely-wooded parkland and gardens etc. and in South Hertfordshire we find them to be abundant under dead Salix bark in riparian situations. They are quick to colonize new situations but we have not found them flying or active at night on trunks etc. Larvae develop under bark and various accounts of their feeding habits may be found; along with the adults they have been quoted as predatory, feeding on scolytid larvae, or fungivorous, feeding on Ascomycetes and other fungi. For much of the twentieth century the species was considered very rare and local in the UK; Joy states ‘very rare under fir bark, London and Cumberland...probably always an importation, while Fowler states ‘very rare from Putney and Blackheath, under dead beech bark...the larvae are carnivorous, preying on Tomicus’. There has since been a great expansion and it is now widespread and locally common throughout the southeast, although it will still be found listed as ‘Nationally Notable A’, and more local and sporadic further west and north. Larvae occur in the same habitats as the adults; they are pale-yellow to white, elongate, straight-bodied and flattened with a distinct broad and hypognathous head. The antennae are 3-segmented, which distinguishes them from some other sylvanid genera e.g. Nausibius Lentz, 1857, Oryzaephilus Ganglbauer, 1899 and Silvanus Latreille, 1804 in which they are 2-segmented. All abdominal segments are approximately equal in length and the ninth bears a pair of long and slender projections mounted on small tubercles. The legs are well developed and widely separated, each bearing a single claw.