I am probably as baffled as you all are! It is not Pegomya seitenstettensis female (although this species has a very long pra). The latter character points to Eutrichota, but it is not like ay European species I have in my collection. The blackish thorax points to something in the E. socculata region, but I know of no species in this group with yellowish hind femur with a distinct black apical part. Whether it is an abnormal female as far as colour of legs are concerned it is difficult to say. Can't see the aristal hairing or the nature of the cruciate setae on frons, or even if they are absent as is tthe case for Eurtrichota.
Norway may still provide some unknown species?

The straight crossvein is a puzzle.
I am still searching through my collection for a female which has such distinctive hind femur, with the basal two-thirds orange yellow, and the apex with a black ring. I only know this from some oriental Pegomya's.