Cantharis rustica Fallen, 1807

Occurs throughout England,Wales and southernmost Scotland; Ayr across to the scottish borders although there are old, unconfirmed, records in the literature from farther north (Alexander). Common and often abundant across southern England, becoming local and scarce in the north; records become scattered north of the Humber. Predominantly a grassland species, found in many habitats where grass is untended and left to seed, open woodland, parkland, agricultural margins etc. A common species throughout the Watford area, occurring in the sweepnet just about anywhere but perhaps the easiest way to see them is on umbels during hot weather. First individuals are seen in mid May and within days they are common, by late June numbers are falling, depending on season they may persist into July. Care must be taken when recording cantharids in general but there are several common large species with dark elytra which should be bought home for careful examination until experience has been gained.

9-13mm. Antennae black with at least two basal segments orange; often up to four more-or-less wholly orange with base of 5-7 lighter, all segments elongate, inserted on front of head inside the level of the inner margins of eyes. Head finely punctate and pubescent, black from base to front margin of eyes. Clypeus convex between antennal insertions. Eyes small and entire, protruding. Temples longer than diameter of eyes, usually obvious in normal setting.

Ground colour of pronotum red, disc with discreet black mark which does not extend to front or hind margins ¹. Finely bordered and rounded but for indistinct hind angles, lateral margin broadly explanate and front margin entire, covering base of head. Basal half raised, culminating in two weak tubercles on disc, Finely punctate, with erect pale setae. Scutellum obvious, punctate and pubescent. Elytra black, not metallic but often appearing silvery due to short, dense and recumbent yellowish pubescence, with strong humeral prominence and two or three indistinct and often incomplete raised longitudinal lines, strongly cross strigose throughout.

Legs variable in colour but always in part red, at least the femoral bases even in the darkest specimens, foretibia black, at least in basal half ². All tibiae with 2 weak terminal spurs on inner side. Third tarsal segment bilobed (cf Rhagonycha), only the anterior claws of each pair with a basal tooth. In Male antennae longer and pro and meso tarsi broader when compared with female.

Description from 4 Watford specimens at X10.

¹ In C.obscura L. (8.5-10mm) this extends to front and margins, In C.fusca L. it extends only to the front margin.

² Foretibia completely red in C.pellucida Fab. (9-12mm) and C.nigricans Muller (7-11mm).