I was out looking for hoverflies - unsuccessfully, as it turned out - when this queen Bumblebee flew over my head and immediately started to rummage in the hedge base, looking for a nesting site:
I rattled off a few shots and a closer look reveals her to be a queen Bombus cryptarum - a recent segregate from Bombus lucorum. The notch in the yellow collar is the clue:
I have been watching the parasitic bumblebee Bombus bohemicus over the last couple of years. This is known to be a parasite of Bombus lucorum, but I wonder if it's also a parasite of Bombus cryptarum, which appears to be the dominant white-tailed species in this location.