Sicus ferrugineus a Parasitod of Bumble Bees
I have yet to see a mating pair this year but I did see these two individuals in separate parts of our garden during the same session.
They fly very slowly and are easy to follow.
Olympus EM-1 (aperture priority), Olympus 4/3 x2 TC, Olympus 4/3 50mm f2 macro, f11, hand-held.
The stereos are crosseye.