Hook:

12 - 18 Tiemco 5262 2XL Nymph Hook

Thread:

8/0 Uni-Thread Black

Body:

1 strand of Medium Olive Betts Zelon twisted into a tight cord (reduce thickness for 16-18 size flies)

Wing:

White polypropylene clipped short

This may be the most simplistic caddis larvae imitation but sure does work great when the Hydropsyche are moving about.  Brought home to Michigan from Montana, this fly works best in the wider, open waters of the AuSable below Mio and the Muskegon below Croton dam.