Genus Bombus Latreille

Taxonomy: Milliron (1971, 1973a, b); Mitchell (1962); Laverty & Harder (1988); Williams et al. (2008, 2014).

Biology. Bumble bees are primarily eusocial with annual colonies, with the exception of social parasites, which in the continental United States are entirely within the subgenus Psithyrus (Heinrich 2004; Husband et al. 1980; Michener 1974; Plowright & Laverty 1984). Nests are commonly made in abandoned rodent nests underground (Husband et al. 1980), but other similar cavities may be used, including walls of houses, and some species typically nest above ground (Richards 1978).