(Panephemeroptera Euephemeroptera Euplectoptera Anteritorna Bidentiseta Furcatergaliae  
Fimbriatotergaliae Fossoriae Ephemera/fg9 Hexagenia/fg1 - Hexagenia/fg2)

Nomen hierarchicum: Hexagenia/fg2 [f:1991; g:1863] (sine Eatonica; incl. Pseudeatonica)

In circumscription fits:

 gen. Hexagenia: Eaton 18831888: 48

 Hexagenia/fg2: Kluge 2004: 241

References. Eaton 18831888: ; Edmunds & Jensen & Berner 1976: * *; Kluge 2004: * * *

Character of Hexagenia/fg2 of unclear phylogenetic status. 

(1) Larval flagellum of antenna with whorls of long dense setae (Eaton 18831888: Pl. 63: 1). The same in Ephemera/fg10.

Plesiomorphies of Hexagenia/fg2. Vestige of tergalius I [see Ephemera/fg9 (4)] is bilamellate (unlike Eatonica/g1-Litobrancha). In male imago gonostylus without projection peculiar for Eatonica/g1.

Size. Fore wing length 1025 mm.

Distribution. America (Nearctic and Neotropical Regions); probably in Palaeogene inhabited in Palaearctic (see Denina in Ephemera/fg9 INCERTAE SEDIS).

The taxon Hexagenia/fg2 is divided into:

1. plesiomorphon Hexagenia/fg3 

2. Pseudeatonica