Proceedings of the Utah Academy of Sciences, Arts, and Letters
In America north of Mexico there are an estimated 4,000 species of bees distributed in approximately 110 genera. In Curlew Valley, 132 species in 33 genera have been identified, and approximately 25 additional unidentified species have been collected. It is likely that at least 225 species in 40 genera should be found eventually. The bee fauna of Curlew Valley can be roughly divided into the following 4 categories on a seasonal basis.
Bohart, George E. and Knowlton, G. F., "The Bees of Curlew Valley (Utah and Idaho)" (1973). All PIRU Publications. Paper 790.