1. Tusks each with 16-25 spines (Fig.1.1); tracheal branches of gills 2-7 not darkly pigmented. (Fig.1.2). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ephoron album
Tusks each with 28-39 spines (Fig.1.3); tracheal branches of gills 2-7 darkly pigmented. . . . (Fig.1.4). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ephoron leukon
Key to Ohio Ephoron Nymph Species
