Platycis minutus (Fabricius, 1787)
This is the only widespread UK member of the family; it is widely distributed throughout England and Wales south of the Wash although generally absent from western areas and there are a few scattered records further north from Yorkshire. It is mostly, although by no means exclusively, associated with ancient woodland and wooded parkland etc. in lowland chalk and limestone districts, it usually occurs in shaded and vegetated situations near Beech (Fagus) and Birch (Betula) but we have also found them swarming over fallen and well decayed Oak (Quercus) completely shaded by dense Beech canopy and on recently cut stumps of Scots pine (Pinus). Adults are present from May to September, peaking in late summer; they are short lived and may be found inside well-decayed logs or, during hot weather, in numbers on herbage around logs and trunks. We have been very fortunate in finding several swarms in local woodlands in Hertfordshire, West Middlesex and South Buckinghamshire during August and September over recent years. They are attracted to flowers e.g. umbels or Rubus if these are present near their host timber, and are thought to feed on pollen and nectar. Larvae develop in dead wood feeding on micro-organisms and they may also be predatory. Pupation usually occurs in the soil or less often so among bark crevices. Sampling generally involves carefully searching likely areas around decaying timber in suitable situations, isolated adults may be found on fallen wood and this should be the cue to begin searching or, if unsuccessful, to return during warm weather and continue doing so. Adults will also occur occasionally among extraction samples of soft decaying heartwood from suitable situations.
5-8mm. A very distinctive species which once familiar will be instantly recognised; elongate and depressed, entirely black but for the elytra, claws and terminal one or two antennal segments red. Head finely punctured and pubescent with proportionally large and convex eyes, deep longitudinal impressions and raised areas between the antennal insertions. Antennae sexually dimorphic being much longer in the male; entirely pubescent and inserted under the lateral margin of the head; 11 segmented, the basal segment bulbous, 2nd small and 3-11 elongate. Pronotum with five broad, deep impressions delimited by sharp costae, anterior and lateral margins with two convex areas. Scutellum black, punctured and pubescent as the pronotum and bilobed apically. Elytra very elongate, usually covering the abdomen although the last segment is often visible in female, with well developed humeral prominences and each with five strongly raised longitudinal costae (including the sutural) separated by a double row of cells formed by transverse ridges, entirely covered with short recumbent red pubescence. Entire underside dark. Legs with short dark pubescence throughout, long and robust with broad femora and curved tibiae Tarsi 5-5-5 in both sexes, tarsomeres 3 and 4 bilobed, more strongly so on pro-tarsi. Claws simple.