Crypturgus subcribrosus Eggers, 1933
At present known mostly from Northern Europe; there a few records widely scattered across central Europe, from France to the Balkans, but the actual distribution remains uncertain as the species was formerly confused with the widespread and closely similar C. cinereus (Herbst, 1793). The present species occurs in all the Baltic countries, but is only really common in Fennoscandia where it occurs in southern Norway, and extends to the Arctic Circle in Sweden and Finland. It was first detected in the UK in 1986, no doubt from continental introductions, and has since spread, but the species remains very local and scarce with records from south east, central and north east England. The species is associated with various conifers; mostly Norway spruce (Picea abies (L.)), but in Europe often with Scots pine (Pinus sylvestris L.) and other species. Adults have been recorded throughout the year but only infrequently so during the winter as specimens may overwinter under bark but more usually within old bark beetle borings, they are active from April until October and peak in abundance during May. Adults sometimes swarm on spring evenings before dispersing to find new host trees, they enter via galleries of larger bark beetles, often those of Orthotomicus laricis (Fabricius, 1792) or Polygraphus poligraphus (Linnaeus, 1758), but also other species. Larvae bore tiny meandering galleries which often intersect or branch, either from the host gallery or from a small brood gallery constructed off the host gallery by the parents. Little is otherwise known of the biology, but despite the species very infrequent occurrence, adults are sometimes very abundant where they occur.
1.1-1.5 mm. Elongate, parallel-sided and cylindrical, body finely and moderately densely pubescent, forebody dark brown, sometimes almost black, elytra and appendages brown. Head concealed from above, strongly convex and almost spherical, with widely transverse and reniform eyes. Antennae short, with an elongate and curved scape, 2-segmented funiculus, and oval club which appear to be single segmented. Pronotum quadrate or slightly elongate, broadest behind the middle and narrowed to rounded angles (from above), surface finely punctured and densely shagreened; this often forming obscure arcuate patterns towards the apical margin, basal margin unbordered and weakly sinuate. Scutellum tiny; triangular and finely punctured. Elytra elongate (about 1.6X longer than wide) and almost parallel-sided from rounded shoulders to a continuous apical margin, apical declivity smoothly curved, striae irregular and formed of wide and shallow punctures which often interrupt the flat or rugose interstices. All tibiae quite strongly broadened from the base, truncate apically and with at least four strong external teeth. Tarsi with five simple segments. Females have a tuft of fine pale setae across the elytral apex.