Synonyms and other taxonomic changes
Long ago pollen-collecting species were sometimes ranked as a subfamily, Bombinae, or even a family, Bombidae, with Psythirus sometimes removed to another higher taxon (Psithyridae) due to its parasitic habits.
Numbers
the tribe contains a single genus
(1)Remarks
Most are primitively eusocial
(2)Print References
Milliron, H. E. 1971. A monograph of Western Hemisphere bumblebees (Hymenoptera: Apidae; Bombinae) I. The genera Bombus and Megabombus subgenus Bombias. Memoirs of the Entomological Society of Canada 82: 1-80.
Milliron, H. E. 1973a. A monograph of Western Hemisphere bumblebees (Hymenoptera: Apidae; Bombinae) II. The genus Megabombus subgenus Megabombus. Memoirs of the Entomological Society of Canada 89: 81-237.
Milliron, H. E. 1973b. A monograph of Western Hemisphere bumblebees (Hymenoptera: Apidae; Bombinae) III. The genus Pyrobombus subgenus Cullumanobombus. Memoirs of the Entomological Society of Canada 91: 239-333.
Mitchell, T.B. 1962. Bees of the eastern United States, volume 2. North Carolina Agricultural Experiment Station Technical Bulletin 152: 1-557.
Stephen, W. P. 1957. Bumble bees of western America. Oregon State College: Agricultural Experiment Station, Technical Bulletin 40. 163 pp.
Thorp, R. W., D. S. Horning Jr., and L. L. Dunning. 1983. Bumble bees and cuckoo bumble bees of California (Hymenoptera: Apidae). Bulletin of the California Insect Survey 23: 1-79.
Warriner, M.D. 2011. Bumblebees (Hymenoptera: Apidae) of remnant grasslands in Arkansas. Journal of the Kansas Entomological Society 84(1): 43-50.
Warriner, M.D. 2012. Bumble bees (Hymenoptera: Apidae) of Texas: historical distributions.
(3)
Williams, P.H. 1998. An annotated checklist of bumble bees with an analysis of patterns of description (Hymenoptera: Apidae, Bombini). Bulletin of The Natural History Museum (Entomology) 67: 79-152.
Williams, P.H., S.A. Cameron, H.M. Hines, B. Cederberg, and P. Rasmont. 2008. A simplified subgeneric classification of the bumblebees (genus Bombus). Apidologie 39 (1): 46-74.