Posted by nick upton on 04-11-2018 21:13
#1
8mm flies on intertidal mussel shells on a shore in Cornwall UK on 11.9.18
Males were courting by opening wings at intervals.
I think these are Fucellia maritima, the more common of the 2 UK Fucellia species, with a more southwesterly distribution than the other species F. fucorum, which I read has black tibia which I don't see her, but I'd wecome feedback/comment on my tentative ID.