#1
Sochi, 15 nov, 5mm, one of a kind, single image.
Sorry, I don't know even family.

#2
Hi Nikita,
It looks like Lauxaniidae genus
Peplomyza.
Peplomyza litura seems to be the most common species, but there are other species in this genus.
Jan Willem
#3
Thank you Jan! Realy, Peplomyza, Lauxaniidae!
There is nice image by Arthropa:
http://arthropa.free.fr/site/gabase.php?page=lisacc&prov=framed&lisact=affich&fiche=-ni-diptere-ailesfumees-plon-0704