Callibaetis are in most every lake during the summer months. Not a hatch that you need to be up and on the lake early, Callibaetis is a gentlemen's hatch. You can sleep in and be at the lake between 10 a.m. and noon, or a little later. It really depends on the wind! The Articulated Callibaetis Emerger has been a very successful pattern for the Callibaetis fishermen on Hebgen Lake in Montana. Try a few you will not be sorry.