Longitarsus succineus

These came to light and I keyed them using Duff. Initially I ended up at Longitarsus aeruginosus which seemed more than a little bit unlikely, so I worked back to see where I might have gone wrong. There were multiple reasons to discount symphyti (especially antennomere 11 slightly but clearly darkened on both antennae of both beetles, no humeral angles) but at the previous couplet I had ruled out succineus based on the proportions of antennomers 4-8. Compared to the diagrams Duff uses to illustrate the difference, I thought they were clearly closer to the illustration for symphyti (aeruginosus should be similar) than the illustration for succineus, but I hadn't actually measured the width and length of the segments to check if they were more than 4x as long as wide or not. I find that measuring and calculating these ratios is always open to error with the distances being so small, which is why I initially relied on visual comparison with the diagrams, but when I did eventually measure them, I realised they were in fact slightly under 4x as long as wide, so fine for succineus. On dissection, by comparing the aedeagi with the diagrams in Duff, succineus seemed to be the best match but the differences from aeruginosus are rather subtle on ventral views (the only view shown in Duff). I found photos online of both species in lateral view, and a paper detailing the differences, and this removed any remaining doubt that my beetles were succineus and not aeruginosus.

male Longitarsus flavicornis showing underparts, pronotum and elytra, close-up of elytral puncturing, atnennae (2 views) and aedeagus (flat and side views), Wendling Beck Project (Norfolk, UK), 23rd June 2026

second male Longitarsus flavicornis showing atnennae and aedeagus (flat and side views), Wendling Beck Project (Norfolk, UK), 23rd June 2026