This is a Denny Rickards pattern. Especially effective when the callibaetis are hatching. Before you see fish rising and rolling, fish this fly deep. Before the actual hatch the nymphs will be getting active as they make their way to the surface. When you see fish rolling, then fish this fly just under the surface. Natural is our favorite, but olive and black are also good colors. Sizes range from #10 to #18.
A.P. (all purpose) Emerger