from the Biodiversity Heritage Library.
The complete title of this book is "Aquatic Insects of California---with keys to North American Genera and California Species
". So the keys to genera may be useful for BugGuide users far beyond California.
Usinger provides a 45 page introduction to aquatic entomology, the second half of which deals mostly with pest control issues. The remainder of the 508 page book has chapters written by various authors on aquatic Collembola, Ephemeroptera, Odonata, Orthoptera, Plecoptera, Hemiptera, Megaloptera, Neuroptera, Trichoptera, Lepidoptera, Hymenoptera, Coleoptera, and Diptera.