The full title of this book is "Aquatic Insects of California---with keys to North American Genera and California Species". Usinger provides a 45 page introduction to aquatic entomolgy, 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, aquatic Orthoptera, Plecoptera, aquatic Hemiptera, Megaloptera, aquatic Neuroptera, Trichoptera, aquatic Lepidoptera, aquatic Hymenoptera, aquatic Coleoptera, and aquatic Diptera. A useful, though dated reference.