Isonychia bicolor, also known as the Slate Drake, is a widely distributed mayfly in the East and Midwest. Unlike most other larger mayflies Isonychia’s hatches are modest in size, however these mayflies continue to emerge in the mid thru the late season. Isonychia nymphs are very fast swimmers, so fish this pattern with lots of action. Also this nymph is ideal to use as a dropper behind a rapidly stripped streamer. See also: Isonychia nymph, dun, and spinner patterns, as well as the Isonychia Set. Tied on a Daiichi 1770 chemically sharpened swimming nymph hook.
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