There is only one genus in this familiy, i.e., Pteronarcys
Males
1. Epiproct, in profile, slender and erect; S9 with longitudinal rectangular hammer bordered on each side by a light colored rectangular area; hind margin of S9 not conspicuously produced rearward and broadly rounded; paraprocts, in profile, boot-shaped . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. biloba
Epiproct, in profile, massively enlarged and curved downward; S9 without a hammer or light colored areas; hind margin of S9 conspicuously produced rearward, narrowing gradually to form a bilobed tip; paraprocts, in profile, triangular . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Bilobed tip of S9, in profile, straight . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. dorsata
Bilobed tip of S9, in profile, curved downward . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. pictetii
Females
1. S8, viewed from underneath, noticeably produced into a rearward projecting subgenital plate or two prominent lobes approximately one-third length of S9; egg hemispherical with well developed collar consisting of a flattened disc enclosed by a vertically striated border . . . . . . . . . . . . . . . . . . P. biloba
S8, viewed from underneath, not produced or barely produced rearward; egg spherical with small collar resembling an overturned watch glass . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
2. S8 hind margin not produced and with or without two small nipple-like projections . . . . P. dorsata
S8 hind margin slightly bowed rearward and with distinct mesal notch. . . . . . . . . . . . . P. pictetii
Key to the Adult Pteronarcyidae of Ohio