Notes:

These patterns were developed by Mike Mercer of Redding, CA around 1989. Mike designed both a nymphal form and an emerger form for Pale Morning Dun, Blue Wing Olive, Callibaetis, Trico's, and Green Drakes. Aspects that highlight his pattern are the use of materials to represent gills behind the thorax and the hard shiny epoxy covering of the wingcase. The use of epoxy on the wingcase has also been used by earlier tiers such as Hal Janssen .
Mike believes that fish are attracted to light/dark contrasts and the darker wingcase with the lighter thorax provides that contrast. His patterns also use dark/light segmentation in the abdomen using pearl flashabou ribbing. The thorax and abdomen dubbing is a blend of colors. Try to include at least three Antron colors to come up with the proper hue. This spectrum will give the fly a mottled effect, more of the natural coloration. The emergent forms generally show a darker wingcase , a trailing shuck, and an addition of a forward wing with hackle. The nymphal form will have a tail represented by 3 Pheasant Tail fiber tips or 3 Ostrich herls, legs represented by partridge fibers, a small dubbed head and is usually weighted.