Helina impuncta

Once I'd got this to Helina this keyed pretty easily to impuncta using Mike Hackston's key. My only quibble was the couplet describing its legs as "almost entirely reddish-yellow". Mostly reddish yellow would be fine as the tibia, femora and coxae were, but given that the tarsi were almost entirely dark (minutely pale at the tips) this seems some way short of the legs being almost entirely reddish-yellow.

My main difficulty with this genus seems to be getting to the genus though... I've failed using Mike's keys and it wasn't straightforward using the RES key. On the latter it all boiled down to whether or not the hind tibia had one or more strong posterodorsal bristles. I thought it had, which took me to Phaonia, but I suspected this was wrong as ObsIdentify app had already indicated there was a pretty good chance this was Helina impuncta. Just to make sure, I took it through Mike's Phaonia key which ended up with Phaonia rufipalpis if the pre-alar was absent or a dead-end if not. I'm not yet very confident identifying the pre-alar bristle, not helped by the fact that I've seen it illustrated as being in different places (on either side of the suture). There is a row of 3 bristles on the side of the thorax behind the suture which I *think* are the supra-alars, and that the front one of these is the pre-alar. If I'm right then it can't be rufiplalpis, but in any case the fly doesn't really look like photos of Phaonia rufipalpis online, whereas it does look very much like photos of Helina impuncta! Just to make 100% certain though, I took another look at that hind tibia. I think the bristles I was looking at were anterodorsals not posterodorsals, and one that is presumably just dorsal (near the apex). Valuable lesson learned!

male Helina impuncta showing close up of hind right tibia, North Elmham Cathedral Meadows (Norfolk, UK), 27th May 2021