Here is a pattern out of Denmark that can turn trouts' heads on streams all over the American West. Caddis make their livings in rocky riffles and then migrate up through the water column to emerge at the surface. The pupal stage is where they are most vulnerable to trout.
On August and September afternoons, while waiting for a hatch of caddis to bring trout to the top, tie on a pupa pattern. Fish it with a floating line and watch for the flash or the sudden movement of the fly line that signals the take.
Tie the Sedge Pupa with brown thread on a No. 8-12 caddis hook. Wrap the underbody with green or yellow tinsel. Wrap the overbody with cream latex stretched tight over the tinsel so that the color shows through. Tie in wings of gray duck then tie in two strands of golden pheasant tail fibers over the back. Finish with a thorax of dubbed hare's mask.
—Gary Lewis, For The Bulletin