This one was surprisingly straightforward to identify. The lack of a sclerite at the base of the lateral hump narrows the field quite a bit, and the other options followed fairly obvious characteristics to Clostoeca, which only has one species, Clostoeca disjuncta.
Trout may feed selectively on caddisflies of this widespread genus. Their lengthy antennae give them the common name Long-Horned Sedge, although that's also a good description of the rest of the Leptoceridae family.