Tiny Baetis mayflies are perhaps the most commonly encountered and imitated by anglers on all American trout streams due to their great abundance, widespread distribution, and trout-friendly emergence habits.
Described by Baumann, R.W. & Gaufin, A.R. (1971) New Species of Nemoura from Western North America (Plecoptera: Nemouridae). The Pan-Pacific Entomologist 47, 270–278.