Heptagenia-borealis
Guides
Metretopus borealis
Metretopus borealis is a mayfly species in the family Metretopodidae, originally described as Heptagenia borealis by Eaton in 1871. It is distributed across the Nearctic and Palearctic regions, with confirmed presence in North America. The species belongs to a small family of mayflies whose members are typically associated with cool, flowing waters.