Isonychia Dry

The Isonychia, also known as the Slate Drake or Mahogany Dun, is a classic dry fly designed to imitate the adult stage of Isonychia bicolor, a mayfly species often found in moderate to fast-moving waters. Known for its robust size and dark coloration, this fly is particularly effective during the late spring through fall months when these mayflies are most active.

During slower or glassy water conditions, fish this pattern with a slight twitch to simulate the mayfly struggling on the surface