"Butterflies of New England" by Larry Weber
"Butterflies of North America" by Jeffrey Glassberg
"Field Guide to Butterflies of North America" by Jim Brock and Kenn Kaufman
"Butterflies of the World" by Alexander B. Klots
"National Audubon Society Field Guide to New England" by Peter Alden et al
"The Audubon Society Field Guide to North American Butterflies" by Robert Pyle
"The Audubon Society Field Guide to North American Insects and Spiders" by Lorus and Margery Milne