Author Institution: Department of Biology, University of Virginia, CharlottesvilleNine species and subspecies assigned to the Propinquus Group, Propinquus Section, of the crawfish genus Orconectes are evaluated on the basis of 1226 specimens examined. Eleven characters are analyzed statistically and 12 more qualitatively, principally by determination of comparative frequencies. O. jeffersoni is judged specifically distinct from O. propinquus and the conspecific O. s. sanborni and O. s. erismophorous. All other taxa of the Group are distinct species. A new species from Iowa is diagnosed, but not described. Two distinct subgroups, Propinquus and Sanborni, are proposed and diagnosed. A lectotype and paralectotypes were designated for Cambarus obscurus Hagen and for Cambarus sanborni Faxon. Standard taxonomic characters in crawfishes are discussed briefly with particular reference to the Propinquus Group
