Stonefly Naiad Exuvia - Plecoptera

Stonefly naiads have long antennae and a pair of long, caudal filaments. They take at least a year to mature, so their presence is evidence that a stream is permanent. Exuviae can be found clinging to vertical surfaces near a stream's edge. Mature naiads crawls out of the water, clings to a surface, and then the winged adult will climb out of its old skin.

I spotted this naiad exuvia on a small bridge that crosses a fast moving stream.