Hexagenia limbata (Hex) Mayfly DunView 2 PicturesThis species is very abundant in Flathead and Whitefish Lakes with a smaller population in lakes of the Swan River Drainage, and a few in Lake McDonald in Glacier Park. This species usually emerges along with Ephemera simulans.
Paraleptophlebia bicornuta (Mahogany Dun) Mayfly NymphView 1 PicturesThis species is interesting because it is common in lakes as well as streams. It is one of the last species of the year to emerge in western Montana. Adults have been collected as late as October 15 weather permitting.