(1) On maxilla [which proximal dentiseta divides into two branches – see Ecdyonurus/fg1 (2)] distal dentiseta divides into several branches divergent nearly from extreme base; thus the distal dentiseta looks as a bunch of stout setae (Kluge 2004: Fig.58:G-H). Unique apomorphy: in other Ecdyonurus/fg1 the distal dentiseta is integral, being either simple or bifurcate like the proximal one.

Among species examined, only a few exceptions are discovered: in Electrogena/g1 necatii [Ecdyonurus] all specimens have distal dentiseta integral, while in related species the distal dentiseta divides into branches (Belfiore, personal communication); among Ecdyonuroides/g1 sp.H4, some specimens have distal dentiseta integral, and some – divided into branches. Possibly, these exceptions are results of secondary reversions.

(2) Primary swimming setae [see Pentamerotarsata (6)] are lost; larval caudalii have only whorls of setae on ends of segments [see Heptagenia/f5=g4 (2)]. Non-unique character (see Index of characters [1.3.66]); among Ecdyonurus/fg1 the same in Leucrocuta/fg1.