Ohio Mayflies

1.         Anterior margin of frontoclypeal apotome with prominent notch (Fig. 1.1), and coxa of fore leg             with long process arising near distal end (Fig. 1.2). . . . . . . . . .. . . . . . . . . . . . . . . .Chimarra

            Anterior margin of frontoclypeal apotome usually lacking prominent notch (Fig. 1.3), although             there may be some asymmetry, if so, coxa of fore leg lacking long process (Fig. 1.4); venter of             head with seta no. 18 located approximately half-way between posterior edge of ventral                         apotome and foramen (Fig. 1.5). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2
2.          Anterior of frontoclypeus slightly asymemetrical (Fig. 1.6). Fore trochantin projecting freely             anteriorly to form elongate, finger-like process (Fig. 1.7); venter of head with seta no.                                 18 approximately half-way between posterior edge of ventral apotome and occipital                     foramen (Fig. 1.8). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Dolophilodes distinctus
            Anterior margin of frontoclypeus evenly convex (Fig. 1.9). Fore trochantin projecting freely only             a short distance, thus forming very short process (Fig. 1.10 ); venter of head with seta no. 18             stouter than any seta on dorsum of head (Fig. 1.11). . . . . . . . . . . . . . . . . . . . . . .Wormaldia