OHIO BEE GUIDE AVAILABLE
Ohio has a new bee guide and you can find it at http://go.osu.edu/ohiobees. 
This book is designed to be used in the field. It contains information on how to identify bee genera of Ohio using binoculars. The study of bees comes with built-in advantages over other groups. In some ways they are the most observable of our animal fauna. During the warm seasons, bees are usually numerous, foraging and resting primarily on flowers, either planted or wild, where they remain relatively undisturbed by an observer standing nearby.
Numerically, bees are also more common and species rich than butterflies. Finally, the impetus for this field guide is to attempt to lure naturalists into taking a serious interest in bee observation. Compared to both birds and butterflies, relatively little is known about bees. Much of their distribution, life history, habitat, and status remains for you to discover.