Trechoblemus micros (Herbst, 1784)
This is a widespread but generally rare species throughout Europe with the exception of the most southern and northern regions, to the north it extends to the UK and the southern provinces of Fennoscandia and to the east through the Caucasus and into Western Siberia, here it is widespread though very local throughout England, Wales and southern Scotland and there are widely scattered records from the east of Ireland. The typical habitat damp grassland or vegetated wet soil beside rivers where the adults live mostly in small cavities within the soil but they have also been recorded from pitfall traps on arable land and from small mammal burrows and on the continent they sometimes occur among plant debris in caves. Adults are present throughout the year but usually occur in small numbers, they overwinter in the soil or under debris and often appear in flood refuse, on the continent often alongside Blemus discus (Fabricius, 1792), they are active from early spring until the autumn but are probably largely unnoticed and under-recorded because of their lifestyle. Breeding is thought to occur in both spring and autumn as both fully grown larvae and adults have been recorded in the winter. They can be sampled by searching among marginal soil and debris when water levels subside after heavy rain or they may appear in suitably placed pitfall traps.
3.8-4.5mm a flat, elongate and rather parallel-sided species, entirely pale to dark reddish-brown, often with the head, pronotum and discal parts of the elytra a little darker, and with very fine pubescence to the pronotum and elytra. Appendages, including mouthparts, pale brown. Head transverse with small, only slightly protruding eyes, robust anteriorly produced mandibles and very long antennae, frons with a variously developed furrow around each eye 2 supra-orbital punctures. Maxillary palpi with all segments elongate, the terminal segment long and tapering, about as long as the penultimate segment. Pronotum distinctly wider than the head; transverse, broadest in front of the middle and sinuate before perpendicular posterior angles, each margin and posterior angle with a single setiferous puncture. Elytra long and only slightly widened behind the middle, striae weakly impressed and unpunctured, the outer ones faint and the sutural stria deepened towards the apex and recurved to unite with the apex of the third stria. Third interstice with 3 setiferous punctures. Males front tarsi with two basal segments asymmetrically dilated.