Check the listing for details. Hackle Dun PMD - Fly Fishing Flies (1 pc). Condition: New. Listed at 1.90 USD. The Hackle Dun PMD imitates a freshly hatched mayfly waiting for its wings to dry before taking flight. Depending on how cold and damp the weather is, mayflies can drift for several feet before flying off. This dry fly and others like it imitate these adult mayflies otherwise known as duns. This pattern is best used during the hatch when mayflies are just starting to come off the water. Trout will be rising to adults on the surface as well as emergers just below. We recommend using a long 9 to 12 foot leader in a 5x or 6x for delicate presentations. Present these dry flies several feet above rising trout. Imitates Pale Morning Duns. Fine dubbing body.