This is the first of it's family I've seen, collected from a tiny, fishless stream in the Cascades. The three species of this genus all live in the Northwest and are predators that primarily eat stonefly nymphs Merritt R.W., Cummins, K.W., and Berg, M.B. (2019).
Troutnut on Jan 12, 2021January 12th, 2021, 2:26 pm EST
This looks to me like an oblique view of a spent mayfly spinner with its wings stuck to the water, possibly Callibaetis as there seems to be a bit of a dark mottling near the front of the wings, but it's hard to be sure in this picture. Callibaetis would certainly make sense for high lakes.
Jason Neuswanger, Ph.D.
Troutnut and salmonid ecologist