This monograph is a continuation of a multiyear study of the genera and species of North American spider wasps (Pompilidae) and their spider host families, genera and species, nesting behavior, ecology, and natural communities. The study enlarges and enhances host preference, nesting behavior, and ecological information for 77 North American pompilid taxa. The first North American Pompilidae records for the families Tengellidae and Segestriidae, both from central coastal California, are reported herein. New host spider genera and species are listed for many of the pompilid species, including the first North American host record for Dipogon (Dipogon) g. graenicheri. The first detailed observations of male and female behavior in Arachnospila arcta are described.