Montana flies tying legend Kelly Galloup ties and explains the design of one of the best mayfly and merger patterns ever tied and created by California fly Tyer Mike Mercer, an Umpqua Signature Tyer, to accurately create cripple emerging mayflies. They are tied in different colors and sizes to match any mayfly hatch you might encounter. This fly is an essential imitation that should be in fly fisher's fly collection. Mike Mercer's innovative fly designs are available from Umpqua Feather merchant's dealers worldwide