Stethomostus fuliginosus

I initially keyed this to genus using Wright but went wrong where I took the femur of the middle leg to the dark in contrast to the pale tibia. In my defence the femur was clearly darker than the tibia, though was perhaps not as pale as implied - and certainly not as pale as on photos of the Blennocampa which I'd keyed it to. Moreover although it was small, it wasn't as small as Blennocampa. In fact the alternative "femur and tibia of the middle leg both brown to black" fitted my insect - it's just that I'd expected that to mean femur and tibia should be the same shade of brown to black, but it doesn't actually say that. So in fact it keyed to Stethomostus, but I wasn't completely convinced and ran it through the RES key too. That uses some different characters but reached the same conclusion.

The RES key also got me to species. I'd made a bit of a mess of the insect by this time so decided I might as well dissect it to examine the saw, although I don't think any of my references (inlcuding Lacourt) show what the saw is meant to look like so that doesn't really help with the ID.

female Stethomostus fuliginosus showing wings, tarsal claw, base of antennae, fore tibial spurs, mesopleuron with pre-pectal groove, scutellum, vertex and saw, Wendling Beck Environment Project (Norfolk, UK), 18th July 2025