Bombus lapidarius is probably the most easily recognised bumblebee species, with its black body and bright orange tail.
The workers have the same colouring as the queen (20-22 mm) but are much smaller (11-16 mm).
The males (14-16 mm) also have similar colouring but have a yellow collar (some yellow hairs in the neck and chest).

Mainau Island, Bodensee, Germany, 9 July 2013