Insecta, Ephemeroptera, Ephemerellidae, Attenella margarita (Needham, 1927): southeastern range extension to North Carolina, USA

New data from the Great Smoky Mountains, in Swain County, North Carolina, USA, extend the geographic range of Attenella margarita (Needham, 1927) (Insecta, Ephemeroptera, Ephemerellidae) southeast by approximately 1,300 km. We confirm that A. margarita has a disjunct east-west distribution in North America, which is rare among mayflies. Head, thoracic and abdominal characters for distinguishing larvae of A. margarita from the sympatric species, A. attenuata (McDunnough, 1925), are illustrated and discussed