This is not a dry fly you tie on to search the water. But keep an eye out for this hatch in April and May and again in the fall. Mahogany dun nymphs make a living in the riffles then migrate to slow-moving edges as they reach maturity. In the slack water near the shore, that’s where the action is.

Don’t cast until you see fish feeding on these blue-winged brown-bodied mayflies. Trout may cruise along the bank to sip dries. Use a long, light leader and keep the shadow of the rod off the water.

Tie the Tilt Wing Dun Mahogany with rusty thread on a No. 12-16 dry fly hook. For the tail, use dun hackle fibers. Wrap the body with a turkey biot tied in tip first. Build the thorax with darker brown dubbing. Tie in a deer hair wing post, trim it as shown then finish with a dun hackle wrapped parachute-style.

—Gary Lewis, For The Bulletin