An Introduction to the Study of Insects . D.J. Borror, C.A. Triplehorn, and N.F. Johnson. Saunders College Publishing. This is the standard text for introductory college entomology courses that emphasize insect identification. Excellent keys to adult stages of all North American insect families.
Illustrations are among the best for completeness and clarity.
A brief description of the biology of each insect family is included. The use of a microscope is usually necessary for most identifications.