1. Cerci with dorsal or dorsal-ventral intercalary hairs, at least on apical half (Fig. 2.6.1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..Alloperla
Cerci without dorsal or dorsal-ventral intercalary hairs (Fig. 2.6.2); setae inserted only at apex of cercal segments. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Thick, depressed black clothing hairs present on all thoracic sterna (Fig. 2.6.3). Mesosternal Y-arms well developed (Fig. 2.6.4). . . . . . . . . . . . . . . . . . . . . . . Sweltsa
Thick, depressed black or other hairs absent from thoracic sterna (Fig. 2.6.5) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Haploperla brevis
Key to the Genera of Ohio Chloroperlidae Nymphs