Roachflies

The adult stoneflies of this family look surprisingly normal given the strange shape of the nymphs. I tried to identify it beyond family level 15 years after collecting it, based on my photos, which are not ideal. It's difficult even to tell the gender for sure because I don't have a good picture of the terminalia, but the body size suggests it's a male, and the species ranges suggest either Peltoperla arcuata or a male Tallaperla maria. One distinctive feature of the original description of this species is that the antennae are paler for a short distance beyond the first two thick, dark segments. That can be seen on this specimen and on a specimen on BugGuide identified as Tallaperla maria.

I'm guessing this is an immature Peltoperla, because it lacks the well-developed setal fringe on the hind femora that would indicate Tallaperla, but it also lacks the dark spots that should indicate a mature Peltoperla nymph.