Yellow-shouldered Splay Erioptera fusculenta
This came to light in a meadow recently (2-3 years?) taken out of arable production. It keyed very straightforwardly using Stubbs. The wing was 4.3mm long.
male Yellow-shouldered Splay Erioptera fusculenta showing wing, thorax from above and side, abdomen from above, halteres and genitalia (before and after clearing), Wendling Beck Environment Project (Norfolk, UK), 18th August 2024