Caddis flies, sometimes called "sedges", like Midges  have four stages of metamorphosis. Egg, larvae, pupa, and adult. However the fisherman must be prepared with 6 basic patterns to successfully imitate the stage being eaten by the trout at the time.

Larvae, emergent pupa,floating pupa, adult  hatching on the surface, adult on the surface ready to fly, and subsurface adult swimming and egg laying.

The G H Sedge  was  introduced by English angler John Goddard in the book The Trout and the Fly. The G stands for Goddard and the H is for Henry (the late Cliff Henry) John's fishing buddy who helped him design the fly. A super, almost unsinkable caddis pattern.

 These are proffessionally tied on Mustad  hooks in size 12