Identification, Images, & Information
For Insects, Spiders & Their Kin
For the United States & Canada
Insects of Western North America
By Edward Oliver Essig. 1926.
The MacMillan Company, 1926
Cite: 248957 with citation markup [cite:248957]
Subtitle: "A manual and textbook for students in colleges and universities and a handbook for county, state and federal entomologists and agriculturalists as well as for foresters, farmers, gardeners, travelers, and lovers of nature."

A thorough compendium of the biology, ecology, economy and distribution of insects in western North America, west of the continental divide.

Essig, E.O. 1926. Insects of Western North America. The Macmillan Company, New York. 766 b/w figs or photos, xi + 1035 pp.

This book can be "borrowed" online via the Open Library web site
This book is freely accessible via an Internet Archive link if one sets up a (free) account with the "Open Library" web site. It's easy and free to do just need to have an email address, and to choose a username & password...then click the link below, and when it loads click the "open a new account" link and follow the instructions there:

After you do so you can "Borrow" the book and read it online (at an Internet Archive link that's provided via the link given above).

Slightly more recent version:-)
It was subsequently reprinted as Insects and Mites of Western North America, though that was around 1929! Still, not a half-bad reference, nicely illustrated given the date. I found it to be virtually the only reference for insects found in the Pacific Northwest when I was growing up. I'd also recommend Western Forest Insects by Furniss if I recall correctly.

"Insects and Mites..."
"Insects and Mites of Western North America" as you point out, was the revised or second edition of Essig's "Insects of Western North America." The 2nd Ed. came out in 1958. Mike

Well, I never was much of a historian, and I'm writing this from work so I couldn't look inside the cover of my copy at home...:-) LOL!