Species Hexagenia limbata

"The current concept of limbata encompasses so much variation that one version or another has been or can be mistaken for other species, including some currently valid species. For example, the thing that keeps me from the wholesale recommendation that nearly all of the specimens in BG’s Hexagenia section be moved to limbata (the vast majority probably are that species) is that specimens of rigida are undoubtedly hiding among them. The same may be true of the limbata section. Something similar is probably involved with the three linked BG specimens that I thought were atrocaudata." (Lloyd Gonzales, pers. comm. 27.vi.10)