Cantharis lateralis Linnaeus, 1758
This native and very widespread Western Palaearctic species is locally common throughout it range, extending from Spain eastwards through Asia Minor to Kazakhstan and into Mongolia, from North Africa; Morocco east to Iran, and north to Southern Scandinavia and the U.K. Here it is widespread and locally common or abundant across Southern England and Wales becoming more sparse and scattered in the west and further north to the Scottish borders. Adults occur from the middle of May until early July, exceptionally into August, in a range of habitats; often in marginal wetland situations but also among vegetation below hedgerows and on damp wooded borders, and in our experience only rarely on open grassland or agricultural land. Typically they will be sampled by sweeping herbaceous vegetation or from flowers of thistles and umbels etc. in suitable situations.
The distinctive elytral colour will identify this species among the U.K. fauna. 4.5-7.5mm Head finely punctured and pubescent, dark from the base to the middle of the eyes, pale anteriorly, antennae dark with several basal segments pale, palpi pale with the terminal segment expanded. Clypeus convex between convex and prominent eyes. Temples long and tapering, typically mostly covered by the pronotum. Pronotum slightly transverse, more so in the male, entirely yellow or occasionally with dark marks on the disc, finely punctured and pubescent throughout. Anterior margin rounded, basal margin straight or weakly curved, sinuate laterally in front of obtuse posterior angles and explanate in the anterior two-thirds. Elytra black with the lateral margins and epipleura yellow, this may be only narrowly visible from above and so specimens will examined carefully in the field. Surface weakly cross-strigose with dense recumbent short pubescence and longer, more erect setae giving the surface a silky effect in some lights. In the male sub-parallel, in the female weakly expanded towards the apex. Legs yellow with the tibiae and tarsi variously but not extensively darkened, often entirely pale. Tarsi 5-segmented; the third segment bilobed, anterior claw of each pair toothed at the base. Eyes smaller and more prominent in the female.