State and Regional References:
Hinchliff, J. 1996. The Distribution of the Butterflies of Washington. Evergreen Aurelians. Oregon State University Bookstore, Corvallis. Layberry, R.A., Hall, P.W. & Lafontaine, D.J., 1998. The Butterflies of Canada. University of Toronto Press, Toronto, ON. 280 pp. Opler, Paul A. 1999. Peterson Field Guide to Western Butterflies, revised edition. Houghton Mifflin Co., Boston, Mass. Pyle, R.M. 1974. Watching Washington Butterflies. Seattle Audubon Society, Seattle, Wash. Stanford, R.E. and P.A. Opler. 1993. Atlas of Western USA Butterflies. Privately published, Denver, Colo. Tilden, J.W. and A.C. Smith. 1986. A Field Guide to Western Butterflies. Houghton Mifflin Co., Boston, Mass.