Bombus (Psithyrus) insularis (Smith 1861) ( citrinus group)

County records: Alger, Alpena, Baraga, Charlevoix, Cheboygan, Chippewa, Crawford, Delta, Emmet, Ingham, Kalamazoo, Luce, Mackinac, Marquette, Menominee, Schoolcraft.

Notes. Social parasite of B. fervidus, B. rufocinctus, B. ternarius and B. terricola . No recent specimens examined from Michigan, and the species has evidently declined more generally in its limited (northern) historical range in the eastern United States, although it remains numerous further north in Canada and further west in North America.