Bumble bees are large, stocky, hairy insects, generally from 6 to 25 mm long. Their bodies are often black and yellow, sometimes with orange, red or white markings.
The hind legs of female bumble bees are modified to help them collect and carry pollen. Their abdomens are tipped with a stinger.
They form organized societies divided into three castes. The queen is the largest insect in the colony and measures from 13 to 32 mm long. Workers – all females – vary from 7 to 18 mm, and males are from 10 to 17 mm long.