If I were restricted to one mayfly pattern, I’d use the Borcher. It was developed for the Au Sable, Manistee and Boardman rivers. It is possibly the most generic of all mayfly patterns.
Hook: Standard Dry Fly Hook
Size: 12 – 18
Wings: Lt. Dun Hackle Tips – Upright and Divided
Tail: Mahogany Ringneck Pheasant Tail Fibers
Rib: Gold Wire
Body: Oak Turkey Wing Quill Fibers or Stripped Hackle Stems
Hackle: Brown and Grizzly Mixed
Directions: I like to begin by tying in the wings and dividing them. Then wrap the thread to the bend and tie in the tail. Tin in the body material (either the turkey wing quill fibers or the stripped hackle stem)and the rib. Wrap the body material to the wings and spiral the rib to the wings. Tie in the hackle and wrap behind the wing and forward. Create a head.
Note: The tail is extra long in three segments.