Resources:

• Apoidea guide from Discover Life (includes some interactive guides, e.g. Bombus): http://www.discoverlife.org/mp/20q?search=Apoidea
• Apoidea guide from Bugguide: https://bugguide.net/node/view/8267
• The Bee Genera of Eastern Canada, CJAI 03 September 25, 2007 by Laurence Packer, Julio A. Genaro and Cory S. Sheffield: https://cjai.biologicalsurvey.ca/pgs_03/pgs_03.html
• Bee Species of Nova Scotia, Journal of the Kansas Entomological Society (2003), pp. 357-384, by S. Sheffield et al: http://nlbeekeeping.ca/data/documents/Bees-of-Nova-Scotia-Sheffield-2003.pdf
• ACCDC NS Invertebrate species ranks: http://accdc.com/webranks/NSINVT.htm