Williams, C. B. 1938. Recent Progress in the Study of Some North American Migrant Butterflies. Annals of the Entomological Society of America. 31 (2), pp. 211-239. https://doi.org/10.1093/aesa/31.2.211
Hood, J. D. and Williams, C. B. 1927. A synopsis of the Thysnopterous family Urothripidae. Annals of the Entomological Society of America. 20 (1), pp. 1-8.