As far as I can tell, this species has only previously been reported from one site in Oregon along the Columbia gorge. However, the key characteristics are fairly unmistakable in all except for one minor detail:
— 4 small yellow spots on
frons visible in photos
— Narrow
occipital spinule row curves forward (but doesn’t quite meet on stem of ecdysial
suture, as it's supposed to in this species)
— Short
spinules on
anterior margin of front legs
— Short rposterior row of blunt
spinules on
abdominal tergae, rather than elongated
spinules dorsally
I caught several of these mature nymphs in the fishless, tiny headwaters of a creek high in the Wenatchee Mountains.