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Hello,

this syrphid with a length of about 10mm is from a wooded small river in the austrian alps. I guess a Baccha species. Is this correct?

There seem to be two rather frequent species Baccha elongata and Baccha obscuripennis. But the photo is too bad to say something, or?

Thanks,
Michael

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Hi Michael,

I'm reasonably sure that it's Baccha. About the two species: I've heard about an ungoing discussion that the two species are in fact (possibly) just one. (The experts here will correct me if I'm wrong or mistaken). I'm not sure but I know for a fact that most experts in the Netherlands state that B. obscuripennis is at most a subspecies of B. elongata. The distinctive difference between the two is a darker wingcolouring (obscuripennis) and a "dusted" (what I would call a) forehead (elongata), and these differences can only be found in males. The females show no differences (so I'm told).

I myself have spotted what I called B. obsucripennis here in my garden (the Netherlands) a couple of times, but in the end they were identified as B. elongata. I would call yours a male Baccha elongata But then again... I'm not familiar with the Austrian species of Syrphidae, let alone Baccha.

Well, I hope this was of any help to you. Good luck!

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Hello,

thank you for the detailed answer. Also in Austria there seems to exist only B. elongata or, if accepted, B. obscuripennis. But you are right, most dipterists seem to look upon obscuripennis as a subspecies.

So I think I have good reasons to sort the picture as B. elongata.

Michael