The mayfly family Leptophlebiidae is well represented in the Southeast. In this study 8 of these states, Alabama, Florida, Georgia, Louisiana, Mississippi, North and South Carolina, and Tennessee, are included. All species known to occur in the region are discussed, and a new species, Habrophlebiodes celeteria Berner, is described. Male and female imaginal stages of Habrophlebia vibrans Needham, the adult females of Leptophlebia bradleyi Needham, L. intermedia (Traver), and Paraleptophlebia volitans McDunnough, as well as nymphs of H. vibrans and L. bradleyi, are also described.