The three eastern species in the Nemobius fasciatus group, generally treated by orthopterists as subspecies or races, can readily be separated as living individuals, and most pinned specimens can now be identified through the use of combinations of easily observed morphological characters. Extensive distribution records, chiefly compiled by listening for singing males, show that the three species have broadly overlapping ranges. Observations on local populations have revealed occasional instances where individuals of two, or all three, of the species are mixed together with no indication of interbreeding. N. allardi , n. sp., previously called N. fasciatus fasciatus (DeGeer), occurs chiefly in grassy and weedy areas in well-drained locations over most of northeastern United States and has a clear musical trill. N. tinnulus Fulton occurs in or near leaf litter in xeric woodland areas in central eastern United States, and its song is a slow trill in which the sound pulses are heard as individually distinct units and can be counted by ear at low temperatures. N. fasciatus (DeGeer), previously called N. fasciatus socius Scudder, is less closely related to the other two species than they are to each other. It occurs in wet situations over nearly all of eastern North America, including Florida, with its northern limits somewhere in southern Canada, south of the limits of N. allardi. Its song consists of a series of buzzy chirps, and is quite distinct from the songs of the other two species and surprisingly like the songs of Miogryllus species. Audiospectrographic analysis of tape recordings of the calling and courtship songs of the three species demonstrate relationships which correlate with morphological evidence. Comparison of the courtship behavior of the males of various Nemobiinae, Gryllinae, and other crickets shows that the sequence can be divided into three major segments, with homologies and analogies suggested in certain cases.