The northeast corner of Yellowstone Park has abundance of light colored mayflies that hatch throughout the summer and early autumn. In order to cover these various hatches with just one pattern the tyers at Blue Ribbon Flies developed the SLS. Although it was originated for the Slough, Lamar, Soda Butte drainage (hence SLS) it can be used anywhere for smaller light colored flies.

When tying, start with the wing tied Comparadun style. Lay the zelon over the back of the wing and bind it to the hook shank with the tying thread down to the tail position forming a slim abdomen. Trim the zelon to form a trailing shuck. Stand up the wing and figure eight a thorax with the dubbing. You Tube has a video of Craig Mathews tying the fly. All materials may be obtained from Blue Ribbon Flies at or by calling them at (406) 646-7642.

Hook : Tiemco 206BL 16 – #20
Wing : Light colored deer hair and Epeorus zelon
Shuck : Epeorus zelon
Abdomen : 8/0 Uni-Thread, Light Cahill
Thorax : SLS zelon dubbing

Alan Bowers

Fly tied by Alan Bowers