The famous nocturnal Hex hatch of the Midwest (and a few other lucky locations) stirs to the surface mythically large brown trout that only touch streamers for the rest of the year.
This Western genus is closely related to Epeorus and its biology is similar. The only species recognized as important to fly anglers is Ironodes nitidus.
While relatively rare in most of western Montana, it is common in several small streams along the east side of Flathead Lake and streams on the south side of the Flathead Indian Reservation.