I think this is a male White-tailed Bumblebee, the common name that applies to three species so similar it would need a DNA test to separate them. Their Latin name reflects this: Bombus lucorum agg. I can't think of another example of flora or fauna where the Latin is an aggregation of several species though no doubt there are other cases.

 Anyway this particular Bombus is feeding on Wild Marjoram (Origanum vulgare), one of the most prolific wildflowers of calcareous grasslands in mid to late summer.