Bombus (Pyrobombus) frigidus Smith 1854

Gibbs, Jason, Ascher, John S., Rightmyer, Molly G. & Isaacs, Rufus, 2017, The bees of Michigan (Hymenoptera: Apoidea: Anthophila), with notes on distribution, taxonomy, pollination, and natural history, Zootaxa 4352 (1), pp. 1-160 : 43

Bombus (Pyrobombus) frigidus Smith 1854 (pratorum group)

County records: None.

Notes. This is an alpine/boreal species recorded from Michigan based on misidentified specimens, but it may nevertheless occur in the state. Milliron (1939) included specimens from Isle Royale identified by Frison as B. frigidus var. couperi . These were re-examined by JG (MSUC, INHS) and were determined to be B. sandersoni , which is consistent with the couperi epithet being a junior synonym of B. sandersoni . Wolf & Ascher (2009) record this species from Oneida County, Wisconsin, which is directly south of Michigan’s Upper Peninsula. Laverty & Harder (1988) also map this species to the Thunder Bay area of Ontario, very near Isle Royale. The distribution of the species is such that the UP is likely part of its southern range in the east ( Williams et al. 2014).