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17 july 2010 The Netherlands, Meppel

In wet rough vegetation along water
3,3 mm long

I found no family for this one
Id. on species level possible?

Klaas

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picture 2

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hi, I would try Opomyzidae / Geomyza sp., but let´s wait
regards

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Yes, thank you!
I have changed the title

Klaas

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Hello Klaas,

To be sure about specimens like this, you need to collect them and study the genitalia. My best guess would be Geomyza hackmani of which we don't have many recordings. However I cannot entirely rule out Geomyza balachowskyi. Did you collect specimens?

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No, the fly is not available ..

Are the two flies you mentioned exactly the same, except for there genitalia?
I can't find differences in the pictures in the gallery

Klaas

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Hello Klaas,

In general, the females of G. balachowskyi have a more banded abdomen (but not always).
In G. hackmani the part below the scutellum is dark and in G. balachowskyi this is much lighter (in general, but not always).
I have seen several exeptions to these "rules".
Studying the genitalia can give you a reliable identification.

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The folowing is worth having.

Drake, C.M. 1993. A review of the British Opomyzidae. British Journal of Entomology and Natural History 6: 159-176.

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oke, thank you both

Klaas

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@Mark-uk: Drake 1993 is certainly worth having, but be warned, on page 165 Fig. 5g: G. balachowskyi (?) must be G. hackmani.