Identification, Images, & Information
For Insects, Spiders & Their Kin
For the United States & Canada
Butterflies Of Ohio Field Guide
By Jaret C. Daniels
Adventure Publications, 2004
ISBN: 1591930561
Cite: 13294 with citation markup [cite:13294]
Similar books by the same author have been published for different states. My thoughts are generally the same as Troy's in his review of the Georgia version.

This is a very handy and easily used reference guide, and contains a wealth of information for it's small size.