Platycis minutus (Fabricius, 1787)       Notable B

Male
Widely distributed throughout England and Wales south of the Wash, scattered records from mid and north Yorkshire and absent from the west country and western Wales. Predominantly from lowland chalk and limestone districts (Alexander). Associated with ancient woodland and wood pastures, generally found on Beech (Fagus) and Birch (Betula) but we have found them swarming over a fallen and well decayed Oak (Quercus) completely shaded by dense Beech canopy (Harefield Place nature reserve, Uxbridge. TQ056872, Sep 2004) and on the stump of a Scots pine (Pinus) felled six months previously (Whippendell wood, Aug 2007). Adults occur during August and September and are short lived, they are found inside rotten logs or, during hot weather, in numbers on herbage around logs. We have been fortunate in finding two such 'swarms' in Whippendell wood, Sep 2006 and Sep 2007. They are attracted to flowers e.g. umbels if these are present near their host timber, and are thought to feed on pollen and nectar (Hurka). Larvae develop in dead wood, feeding on micro-organisms in fluids, they may also be predatory (Hyman and Parsons). Pupation usually occurs in the soil, less often so in bark crevices. Over the last 25 years or so we have found many colonies of these outside our area; from Uxbridge, Cowley, Denham and throughout the various Ruislip woodlands. Swarms can hardly be missed by the alert coleopterist but when during cool weather a single specimen turns up in the sweep net the area should be searched thoroughly, in our experience they do not wander far from their host timber.

5-8mm. A very distinctive species which , once familiar, will be instantly recognised, initially one should count the tarsal segments as various heteromera are superficially similar. Elongate and depressed, entirely black but for the elytra, claws and last one or two antennal segments. Antennae 11 segmented; 1st segment bulbous, 2nd small, 3-11 elongate. Inserted under front of head, entirely pubescent and much longer in male. Head finely punctate and pubescent, with deep longitudinal impressions and raised areas behind antennal insertions, more prominent in female. Pronotum with five broad, deep impressions bordered with strongly raised cuticle including front and lateral margins, with two raised areas basally enclosing a median longitudinal impression. Scutellum black. Elytra very elongate, usually covering abdomen although last segment often visible in female, with well developed laterally protruding humeral prominences. Each with five strongly raised longitudinal lines including sutural and a less prominent line between each, numerous small transverse lines connect these, covered with short recumbent red pubescence. Underside completely black. Tarsi 5-5-5 in both sexes, segments 3 and 4 bilobed, strongly so on protarsi. Claws simple, yellow.

Platycis cosnardi (Chevrolat) has antennae entirely black and pronotum red/brown, darker centrally. Very rare, only from the Wye valley, all records from May. (Airey Shaw, H.K.,1944 Ent.Mon.Mag. 80:204-205.)

Description from 4 Watford specimens at X10


Female

Male

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