Mayflies are the preferred food for many trout populations.Β Mayflies are very vulnerable during their emergence on the water.Β Some even have a hard time with the transition and become crippled.Β Trout love this stage of a hatch.Β While technically only baetis and callibaetis (mayflies and blue wing olives/blue duns) have an aquatic emergence stage, some caddis, stoneflies and midges can become crippled and become easy prey.Β Its a must-have group of flies.Β Here is the one of largest selection of emergers and cripples that you will find anywhere.