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Hi,
This fly was captured above Chambéry, Savoie, France (April 25, 2011). Length from antennae to tip of wings: 5.5 mm.
Using The Muscidae (Diptera) of Central Europe from Gregor et al, I ended on Macrorchis meditata. Would this be correct?
Widus

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Coenosia sp.

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Thank you Stéphane,
I was not very far from Coenosia. In fact, just above in the identification key that said:

53. Postocellar setae nearly as long as outer vertical setae; tegula, basicosta and trochanters yellow; mid tibia with a single posterior seta; hind tibia with one anterodorsal seta ->Macrorchis
- With a different combination of characters ->54 (leading to Coenosia).

However, the characters described for Macrorchis in 53 seem to fit with the individual on the picture. I provide the details below where I tried to place the different elements. Which mistake do I make here?

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Well, if you read the genus definition p. 181, you will see : genus characterized by 2 strong presutural dc ; there is only one strong prst dc on your fly (+ a very smaller one dc in front). That makes it a Coenosia. Macrorchis have also all femora black, except at tip. But I agree this part of the key is very misleading.

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I am trying to go on with the identification but I stumble on a term at point 17 in the Coenosia identification key: what are squamas?

OK I got it

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Now what about the sex of the fly: how can we tell?

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Without looking at my book, you can start at 67 ! ;)

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Thanks.
On I go to 67 but :| already stuck at 71 because I do not see any seta on the proepisternum (I just see one seta on the proepimeron). HELP

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OK another view and I am back on track: 1 seta on the proepisternum

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Well I end up on Coenosia testacea. I do not think it is C. infantula because of the wing nervation (C. infantula has the section of M1 vein between both crossveins on wing shorter than the apical section of CuA1).

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Nice demonstration ! :)