Rainbow Greenclock Poecilus versicolor

(In an earlier version of this page I accidentally used the incorrect vernacular name for this species - apologies for any confusion).

The keel on the first 3 segments of the antennae pointed this to genus Poecilus, then a combination of reddish antennal bases, the lack of distinct punctures on the head, the broad flattened area on the sides of the pronotum and the arrangement of depressions on the pronotum all pointed to versicolor, the commonest member of the genus in Norfolk.

Rainbow Greenclock Poecilus versicolor showing basal segments of antenna, frons and pronotum depressions, North Elmham Cathedral Meadows (Norfolk, UK), 19th April 2021

Rainbow Greenclock Poecilus versicolor, North Elmham (Norfolk, UK), 8th May 2020

Hackston's key to genera requires Poecilus to have smooth claws, as opposed to "Claws toothed or comb-like on the inner surface, at least at the base." I don't recall taking the non-smooth option without there being a clear comb before, but don't those shallow projections near the bases of the claws (see third photo below) qualify as teeth? Anyway, it was fairly obvious this was Poecilius, and either versicolor or cupreus. The frons wasn't completely smooth but anything that might be described as punctures was certainly less distinct than on the cupreus I examined last year (where the punctures were extensive and well-defined, albeit very small). There were a few clearer punctures above the rear of the eyes but certainly not extensive. The hind tibia had 8 internal setae so that didn't help confirm the ID but the position of the inner laterobasal foveae on the pronotum did support my ID as versicolor. This was found in a pitfall trap.

Rainbow Greenclock Poecilus versicolor showing hind tarsal claws, forns (2 views), base of pronotum side, antennal segments 1-3 and hind tarsus, Wendling Beck Environment Project (Norfolk, UK), 4th to 5th April 2025