An analysis of ecology, nesting behavior, and prey in 40 North American, Central American, and Caribbean species of the pompiliformis, terminates, brullii, obscuripennis, and julliani species groups is made. Nesting behavior, prey, and ecological components analyzed include number of generations per year, nesting site, aggregation and nest density, pre-existing burrow use, burrow excavation and leveling behavior, presence or absence of tumulus and temporary closure, orientation, hunting, prey capture, malaxation, mutilation, manner of transport, provisioning time, manner of nest entry, final nest closure, nest structure and dimensions, type and stage of prey, prey size, number of prey per fully provisioned cell, placement of prey in cell, wasp's egg, seasonal trends in nesting, cleptoparasitism, and adaptability.