Philorinum sordidum (Stephens, 1834)
This very widespread species occurs throughout much of Europe and Mediterranean North Africa east to Turkey and extending north to Denmark and the UK. Beyond Turkey the range does not extend into Asia, and through Europe generally it is a rare and very local insect e.g. in France it is known from only a few records in the south-west and in Poland it was first recorded in 2000 and remains very rare. The UK seems to be the exception as here it is widespread and locally common across England and Wales, extending sporadically north to the Scottish Highlands and north-east Ireland and there are records from Anglesey, Lundy and Scilly. Typical habitats include warm, open and dry moorland and heathland, wooded margins and occasionally parkland, and on the continent they occur to low mountain altitudes in the Alps. Adults occur from early spring in sunny situations on a variety of flowers where they are known to feed on pollen, they are more particularly associated with broom (Cytissus) and gorse, (Genista and Ulex spp.) and adults may be found on broom foliage early in the year before the flowers develop. Little is known of the biology but adults occur through the summer and may overwinter near to the host, they are readily found by beating foliage and flowers and have been sampled from yellow water traps left near host plants.
Adults are small, 2-3mm, elongate and flattened, parallel-sided and discontinuous in outline, entirely black or with the pronotum and/or elytra variously brown, the dorsal surface is finely pubescent, the forebody closely and rather strongly punctured and the elytra more finely and less closely so. Head smoothly convex, without impressions or structure, eyes convex and prominent and temples strongly narrowed ocelli often difficult to see among the punctures. Mouthparts pale. Antennae dark with 4 or 5 basal segments pale; slender and without transverse segments; 6-10 weakly but distinctly elongate. Pronotum transverse and more or less flat across the disc, with rounded lateral margins and indistinct angles. Elytra finely punctured and without any trace of stria; elongate and parallel-sided, with rounded shoulders and separately curved apical margins. Abdomen strongly bordered, tergites very finely punctured and with weak microsculpture which is transverse across the base. Legs long and slender, pale or with the femora and tibiae variously darkened. Posterior tarsi very long; as long as the tibia, with the first and fifth segments each as long as 2-4 combined.
Collecting this species from the host plants is a good guide to its identity, and if the ocelli cannot be seen the size and general form will eliminate it from other subfamilies. The punctation of the forebody coupled with the slender antennae and long posterior tarsi will distinguish it from other Omaliinae.