The Cornell University site Biological Controls is a very useful guide to beneficial insects and biocontrols of pest insects and diseases. It shows how these beneficial insects and techniques can help you garden more successfully and contains helpful photographs.
Bugs of Washington and Oregon
Bug enthusiasts and amateur entomologists will appreciate this field guide from The Discovery Channel's "Nature Nut" John Acorn and illustrator Ian Sheldon. Bugs of Washington and Oregon, by John Acorn (Lone Pine Publishing, 2001; $12), is an entertaining book that brings out the personality of each insect, while detailed illustrations bring them to life. From delicate and beautiful butterflies to scary and venomous spiders, all of the insects in the book are grouped and color-coded for easy identification. A quick-glance key to bugs at the beginning of the book enables the reader to easily locate each insect.