Choleva angustata

This was collected from a pitfall trap (in propylene glycol, so no live photos). It keyed fairly straightforwardly up to the choice between angustata and glauca but I had difficulty deciding if the 8th segment of the antenna was closer to 2x as long as wide or 1.5x as long as wide (by eye I thought it was closer to 1.5x but my measurements seemed to suggest it was nearer 2x). With glauca being much scarcer it was always likely to be angustata, but I needed to see the genital capsule to make sure. I made the mistake of flattening this to view it two-dimensionally but that way it didn't quite match any of the diagrams for any species (though was closest to angustata). I realised that had I left it rounded (the two side plates were almost perpendicular to the central plate upon removal) the proportions of the side plates matched the diagrams in Duff and Hackston much better (I tried to restore this - see the last photo). In removing it the side plates had also separated from the central section more than shown in the diagrams, but allowing for that it all matched up with angustata pretty well (and clearly wasn't glauca). The notch at the apex of the central section isn't shown in Duff but is (to a degree) shown in Hackston.

The appendages of this beetle were quite delicate and damaged easily as I tried to clean it from all the mud and gunk it acquires when sharing a pot of propylene glycol with 13 slugs. In the photos below the first one shows the right antenna broken off between the 7th and 8th segments and the left one intact, but by the time I took the close up photo to show the dimensions of segment 8, the other antenna had also broken, between the 8th and 9th segments. Therefore the terminal segment to the left of that photo is the 8th segment.

female Choleva angustata showing head and pronotum, apex of elytron, elytral hairs, antennal segment 8 (and 7) and genital segment (2 views), Wendling Beck Environment Project (Norfolk, UK), 29th to 31st March 2024