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.
I lost track of this specimen before I could get it under my microscope, but caddis expert Dave Ruiter was able to identify it from pictures as Glossosoma, with an uncertain suggestion of G. alascense as the most likely species.
This caddisfly was collected from Rock Creek in Montana on July 9th, 2019 and added to Troutnut.com by Troutnut on July 18th, 2019.