Stephen, W. P. (1954). A revision of the genus Colletes in America North of Mexico (Hymenoptera, Colletidae). University of Kansas, Entomology.
Part 1 (150-248)
Part 2 (249-348)
Part 3 (349-448)
Part 4 (449-527)
Index, figures, and maps. (502-527)
cite:1839384