1. Gills present in the ventral neck region (Fig. 2.5.1) . . . . . . . . . . . . . . Amphinemura
Gills absent from neck region and submentum (Fig. 2.5.2) . . . . . . . . . . . . . . . . . . 2
2. Pronotum angular at corners and with a definite lateral notch (Fig. 2.5.3) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Soyedina vallicularia
Pronotum with rounded corners and without a lateral notch (Fig. 2.5.4) . . . . . . . . . 3
3. Pronotum with a distinct single, lateral fringe of bristles that are usually about equal in length, but are sometimes longer on corners (Fig. 2.5.5); meso-and metanota and wingpads with distinct fringe of bristles on lateral margins; foretibia with combination of numerous bristles and sparse (8-10) fine outer fringe of hairs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Nemoura trispinosa
Bristles of pronotum tiny (except Ostrocerca) and not arranged as a distinct regular lateral fringe (Fig. 2.5.6); foretibia with combination other than numerous bristles and sparse, fine outer fringe hairs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
4. Foretibia with two rows of moderately long robust bristles and sparse fringe of fine hairs (Fig. 2.5.7); pronotum with short, irregularly spaced marginal bristles (Fig 2.5.8). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ostrocerca
Foretibia without distince rows of robust bristles, and fringe of fine hairs complete or sparse (Fig. 2.5 9); pronotum with tiny inconspicuous bristles; tibia with short, stout bristles along outer margins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Prostoia
Key to the Genera of Ohio Nemouridae Nymphs
