The half-black bumblebee (Bombus vagans) is a small bumblebee with a wide distribution in North America, its range extending from Ontario to Nova Scotia and southward to Georgia.

[2] Bombus vagans is a common species of bumblebee with a medium-length tongue.

[4] This bee comes out from hibernation quite late in the year with the first queens being seen in early May in Maine,[3] and workers being on the wing from June to August.

The queen favors apple and plum blossom while the workers appreciate red clover, Penstemon, Asclepias (milkweed), Cirsium (thistle), Eupatorium and Spiraea (meadowsweet).

Unlike most other species of bumblebee in the region, it forages in shady forest habitats.