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.
This one seems to lead to Couplet 35 of the Key to Genera of Perlodidae Nymphs and the genus Isoperla, but I'm skeptical that's correct based on the general look. I need to get it under the microscope to review several choices in the key, and it'll probably end up a different Perlodidae.
Definition of 'cubito-anal crossvein' in Stoneflies
Definition of 'cubito-anal crossvein' in Stoneflies
Cubito-anal crossvein: The cubito-anal crossvein (denoted cu-a) is a crossvein connecting the cubitus to the first anal vein, typically very close to the base of both veins in stoneflies.
These other words reference the same concept: cubitoanal crossvein, cu-a crossvein, crossvein cu-a, cu-a.