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This small Ephydrid (some 3 mm) was abundant in dry grasses with pools of water in a birch forest near Copenhagen. Along equally numerous Paracoenia fumosa.

I suppose it is Coenia sp. but according to the genus key in the palaearctic manual Coenia sp. should have an absent or very weak and short postpronotal seta. The specimens I caught all have a postpronotal of about the same size as the posterior notopleural. Going by the book it should be at most 1/4 as long.
So either am I looking at the wrong bristle or this is something other than Coenia sp.

If it turns out to be Coenia sp. after all how do you separate the species?

Collected 22. iii 2010 near Copenhagen.

Greetings,

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Second picture!

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This is Coenia - I think palustris, but difficult to be certain. It looks like the lower picture may be a male, in which case it's not curvicauda (which has very large genitalia), and the pale haltere also suggests palustris.
You may be confusing the presutural supra-alar with a postpronotal bristle - there should be a short (though still quite strong) postpronotal, if I remember correctly.
I have found that palustris tends to have bronze-green reflections whereas curvicauda has purple-bronze reflections, but this is not in itself a good character to use.
Cranefly can tell us whether vulgata is easily separated from these two, but I don't think it occurs in Denmark.

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C.vulgata is registered in Kazakhstan and Russia (Siberia). This fly is to be C.palustris.

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Thank you very much both of you. Coenia palustris it is then.

It is slightly embarrasing to admit it but I was looking for the postpronotal in the opposite end of the dorsum (i.e. on the postalar callus) :|
The flies I collected have two short but rather strong bristles on the postpronotum. One has three.
At low magnification the colour is dark greenish with a hint of bronze. No males are sporting large genitalia.

I'll write Coenia palustris on the labels.