1. Cervical or submental gill remnants present . . . . . . . . . . . . . . . . . . . . . . . . . Amphinemura
Gill remnants absent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
2. A1 and A2 veins united near forewing margin; cerci small and unsclerotized; male epiproct bilaterally asymmetrical. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Soyedina vallicularia
A1 and A2 veins not united in forewings; cerci variable; male epiproct bilaterally symmetrical . 3
3. Epiproct enlarged into a probe like structure on abdominal tergum 10; vesicle usually present on abdominal sternum . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Males, 4
Epiproct simple, tergum 10 without probe like structure; vesicle absent form sternum 9 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Females, 6
4. Cerci elongate, sclerotized or with subapical spines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Cerci unmodified and poorly sclerotized . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Prostoia
5. Cerci with subapical spines; abdominal segments uniformly sclerotized and about equal in width; apex of abdominal sternum 9 only slightly produced . . . . . . . . . . . . . . . Nemoura trispinosa
Cerci elongate, curved and without subapical spines; anterior abdominal segments weakly sclerotized and narrower than segments 9 and 10; apex of abdominal segment 9 produced into a long probe which extends almost to, or beyond tips of cerci . . . . . . . . . . . . . . . .Ostrocerca
6. Abdominal sternum 7 covers most or all of sternum 8; cerci membranous and apically rounded . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Nemoura trispinosa
Abdominal sternum 7 covers less than half of sternum 8; creci membranous and apically rounded. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
7. Subgenital plate of abdominal sternum 8 covers most of sternum 9; sternum 7 sometimes with median nipple-like projection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Ostrocerca
Subgenital plate of abdominal sternum 8 covers little, if any of sternum 9; sternum 7 without median nipple-like projection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Prostoia
Key to the Adult Nemouridae of Ohio