Swept from flowering willow at same time as Egle ciliata, this is a much smaller fly. I think it is another species. Comparing with Michael Ackland's drawings and using his key I keep coming back to Egle parva except that the cercal plate does not seem to be narrowed basally. Almost fits E. minuta better but epandrium not hairy laterally. Now confused and stuck. Wrong Genus? Herts. 16 March 2021.
Great pictures, Colin. These are so difficult from photos though, however good they are. Look again at the epandrium - your last two pictures seem to show setae which may be on the epandrium - at the angles they're taken at it's difficult to tell just where they arise. I think this is probably E. minuta, but I'm not certain about it. Michael would have known, of course, but sadly he's no longer with us.
Thanks Howard. Here's another more dorsal view of the epandrium. Not very clear but under the scope I can see a bunch of hairs towards the apex of the epandrium on each side. Michael's actual choice is of "Epandrium with setulae on lateral parts" or "Epandrium bare on lateral parts". I think I interpreted "lateral parts" as "lateral margin". E. minuta seems to be more likely from this viewpoint. I don't think I am able to see or dissect out the pregonite.
That looks right Colin. I can't be absolutely certain, but it looks like E. minuta to me.
Thanks again Howard.