When the trout refuse every other beatis I show them I go to this fly. Dress this with Murray's Liquid Dry Fly Floatant, taper down to 7X and cast this 3 feet upstream of your rising trout. Even though this is a fragile fly you can keep it on the surface film with this floatant.
Don’t be fooled by the simplicity of this fly. The split tail, biot body (nicely segmented like the natural) and CDC wing result in an irresistible combination to trick picky trout. Particularly effective in smaller sizes.