While the Gold-Ribbed Hare's Ear may be a serviceable imitation of the Callibaetis nymph it bears scant resemblance to one. The Callibaetis nymph is a "swimmer" and, as such, has a much longer and more graceful appearance than the typical GRHE nymph pattern. I tie my imitation on a size 12 Tiemco 2312 (a 2x long, 1x fine hook, with a slightly curved shank and straight eye). The tails are marabou fibers which are then wound up the shank to form the abdomen and reinforced with a fine gold or silver wire rib. The secondary fibers, growing longer from tip to butt, form a slight taper as well as simulating the gills along the sides of the abdomen. I tie in a strip of pheasant tail just behind the eye, leaving the tips (long enough to form the legs) stick out over the eye and lay it back over the hook as far as the forward end of the abdomen. I use a little dubbing to bulk up the thorax then bring the pheasant strip back over the top, tie it down and clip it off. I tease the tips down and back to form the legs and finish it off with a small head.
This has proven to be a very effective pattern.