How to know the butterflies :
a manual of the butterflies of the eastern United States /
by John Henry Comstock and Anna Botsford Comstock.

APA Citation

Comstock, J. Henry., Comstock, A. (Botsford) 1854-1930. (19251920). How to know the butterflies: a manual of the butterflies of the eastern United States. Ithaca, N.Y.: Comstock Pub. Co..

MLA Citation

Comstock, John Henry, 1849-1931, and Anna (Botsford) 1854-1930 Comstock. How to Know the Butterflies: a Manual of the Butterflies of the Eastern United States. Ithaca, N.Y.: Comstock Pub. Co., 19251920.

Warning: These citations may not always be complete (especially for serials).