Stenostola dubia (Laicharting, 1784)

This species is locally common throughout Europe, extending east to the Caucasus and north to The UK and southern Fennoscandia; here it is very local though not uncommon across England north to the Scottish border and there are a few widely scattered records from Wales. The typical habitat is open mixed woodland and parkland where the hosts, which include a range of deciduous trees but more especially lime, are present in various stages of growth and decay. Adults occur from May until July, they are active in warm weather and may be observed feeding on host foliage or, more rarely, various flowers in bright sun. Mating occurs on leaves or flowers early in the season and females oviposit in small dead branches, especially where these have fallen and are in contact with the ground. Larvae feed beneath the bark until they are about half grown and then tunnel into the xylem where they continue feeding until the following spring although in smaller branches they will feed exclusively beneath the bark. Pupation occurs in April or May in a curved subcortical cell and adults eclose after a few weeks, they remain in the cell for a while to harden before leaving through a circular emergence hole.

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​This rather nondescript longhorn is distinctive among the UK fauna due to the habitus and drab colouration, if in doubt the claws should be examined; they have a long internal lobe extending from the base to about two-thirds from the tip, giving the impression that each is deeply split longitudinally. 9-14mm. Very elongate, with broad shoulders and long elytra which widen slightly towards the apex, entirely dark grey to black, usually with a slight green or blue reflection and appearing silky due to the fine and rather dense dorsal pubescence, often with a line of paler pubescence to the vertex and each lateral pronotal margin, scutellum with dense pale pubescence so contrasting against the pronotum and elytra. Head large and transverse, with weakly convex vertex and frons and large eyes that curve around the antennal insertions. Antennae entirely dark; in the male reaching beyond the elytra apex by one or two segments, in the female reaching the apex or only slightly overlapping. Pronotum cylindrical and quadrate or slightly elongate, parallel-sided or nearly so and strongly and moderately densely punctured. Elytra elongate, with rounded shoulders that are much wider than the pronotal base and separately rounded apical margins, surface without striae but sometimes with obscure longitudinal ridges, often one from inside the shoulders, densely and quite strongly punctured and (usually) vaguely cross-rugose. Legs long and slander; the hind tibiae extending just beyond the elytral apex, entirely black with rather dense pale grey pubescence. Claws orange, contrasting against the dark tarsi.