Four-spotted Flutter Fly Palloptera umbellatarum

Also just called Four-spotted Fly (by Brock in Britain's Insects).

When I examined this specimen at the end of 2022 I was immediately reminded of a couple of Geomyza tripunctata that I had recently identified. However despite some superficial similarities there were some major differences and it turned out that it belonged to an entirely different family altogether. Various references stress that this species needs to be carefully separated from the similar Dumbell-spotted Flutter Fly Palloptera modesta, the main differences being that umbellatarum lacks the bristles along the hind section of the mesopleuron which are present in modesta and some small differences in the wing pattern. Perhaps clearest of the wing-pattern differences is the presence of a spot on the anal vein in umbellatarum: this is not apparent in my photos of the live insect but was quite clear when I eventually examined the insect (despite the spots having largely faded by this time).

Four-spotted Flutter Fly Palloptera umbellatarum showing mesopleuron and (slightly faded) wing, North Elmham (Norfolk, UK), 17th July 2021