The Muscina genus is characterised by a striped thorax, a red tip to the scutellum and the discal vein turning up so that the first posterior cell is narrowed towards the wing apex.
There are four UK species. Muscina levida is 6-8.5mm, has black legs, black antennae and palps, and a posterior cell that narrows gradually so that the width at the wing tip is about 70% of the widest part of the cell.
Muscina stabilans has yellow legs.
Muscina prolapsa has black legs, yellow on part of the antennae and palps, and the posterior cell is more extremely narrowed at the wing tip to around 40% of the widest part.
See also Muscina levida on NatureSpot.
Other beasties on this site include Campyloneura virgula.
See in the gardens of Chiswick House in July 2023.