Figures: 29, 53, 99, 158, 197, 229
In addition to the Rhithrogeninae characteristics, the following combination of characteristics will identify the genus:
Larvae of Ironodes are differentiated from other Nearctic Rhithrogeninae by the combination of a vestigial median caudal filament (Fig. 29), small lamellae on gills 1 (Fig. 99), a dense fringe of setae on the anterior margin of the head capsule (as in Fig. 38), and incisors on the galealaciniae that are not greatly enlarged (Fig. 53). Additionally, gills 7 lack fibrils, and all known species have small paired dorsal tubercles on the abdomen.
The absence of a transverse suture on the mesonotum (as in Fig. 114) will differentiate Ironodes adults from all other Nearctic Heptageniidae except Epeorus. All Ironodes males have penes that are widely separated and lack titillators. Some Nearctic Epeorus have similar penes, but differ in having poorly developed crossveins in the basal area of the forewings. The well-developed basal crossveins (fig. 197) will also separate females of Ironodes from those of Epeorus in North America.
Western Nearctic (Fig. 229).