Austin, George T., and Andrew D. Warren (2002). "Taxonomic notes on some Neotropical skippers (Lepidoptera: Hesperiidae): Pyrrhopyginae and Pyrginae". Dugesiana, vol. 9, no. 2, 15–49.
Opler, Paul A. (1999). A Field Guide to Western Butterflies, Second Edition, xiv + 540.
Opler, Paul A. & Andrew D. Warren (2005). Butterflies of North America, pt. 4: Scientific Names List for Butterfly Species of North America, north of Mexico, 80.
Pelham, Jonathan P. (2008). "A catalogue of the butterflies of the United States and Canada with a complete bibliography of the descriptive and systematic literature". Journal of Research on the Lepidoptera, vol. 40, xiv + 658.
Further reading
Arnett, Ross H. (2000). American Insects: A Handbook of the Insects of America North of Mexico. CRC Press.