No, it isn't Opomyzidae. Wing pattern as in Pallopteridae, but as far as I understand, Pierreis right, it is really Lauxaniidae, I think Minettia inusta.
Nikita
Thanks Nikita and apologies to Pierre, I'll look more closely next time before jumping to conclusions - I do have Minettia inusta in my collection but had not remembered it. (At least I got the question marks right )