This is a solitary digger wasp, probably genus Ectemnius. The hoverfly underneath it is its prey, which it has paralysed and will carry back to its nest to feed its larvae. Taken at the Triangle this afternoon. I saw it happen and the hoverfly buzzed frantically and very loudly for a bit before succumbing. I also saw the wasp carrying the hoverfly – I guess it stopped here for a rest.
