Scaeva selenitica at Nitten

Back on the 16th July, I set a few light-traps in the Nitten Field at Mewslade in the hope of trapping some migrant moths, as the weather looked favourable. It transpired that it wasn't especially good for migrants, although there was an excellent selection of resident moths along with a selection of non-lepidopterans. Perhaps the pick of the crop were a couple of Scaeva selenitica, an uncommon partial migrant hoverfly, which looks superficially like the much commoner S. pyrastri. It's the first time I have seen this fly in Gower, so I assume they were immigrants rather than from a resident population.