1. Basal (1st) tarsal segment as long or longer than apical (3rd or distal) segment (Fig 1.1) . . . . . . . 2
Basal tarsal segment much shorter than apical segment (Fig 1.2). . . . . . . . . . . . . . . . . . . . . . . . 5
2. Mid tarsal segment at least 2/3 length of basal segment in lateral view (Fig 1.3). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Taeniopterygidae
Mid (2nd) tarsal segment less than 1/3 length of basal segment in lateral view (Fig 1.4) . . . . . 3
3. Cerci multisegmented (Fig 1.5) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Capniidae
Cerci one segmented (Fig 1.6) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
4. Apical segment of labial palp enlarged and circular (Fig 1.7); wings flat at rest; forewing often with an X-pattern of cross veins at cord (Fig. 1.8). . . . . . . . . . . . . . . . . . . . . . . . . . . . . Nemouridae
Apical segment of labial palp similar to preceding segments (Fig 1.9); wings rolled around sides of abdomen at rest; forewing without an X-pattern of cross veins at cord (Fig 1.10). . . . . Leuctridae
5. Forewing anal region with two rows of crossveins (Fig 1.11); basal two abdominal segments with ventral gill remnants (Fig 1.12). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Pteronarcyidae
Forewing anal region with, at most, a single row of crossveins (Fig 1.13); basal abdominal segments without ventral gill remnants (Fig 1.14). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
6. Posterior margins of abdominal sterna with comb setae (Fig 1.15); lateral margins of frons nearly parallel, frons quadrate (Fig 1.16). . . . . . . . . . . . . . . . . . . Peltoperlidae, Peltoperla arcuata
Posterior margins of abdominal sterna without comb setae (Fig 1.16); lateral margins of frons convergent, frons not quadrate (Fig 1.17). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
7. Forewing vein 2A often forked between anal cell and wing margin (Fig 1.18); pronotum ellipsoidal (Fig 1.19); hindwing anal region usually with less than five longitudinal veins (Fig 1.20); body color often pale yellow or green in life. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Chloroperlidae
Forewing vein 2A usually not forked beyond anal cell (Fig 1.21); pronotum usually with acute or narrowly rounded corners, shape more rectangular (Fig 1.22); hindwing anal region with five or more longitudinal veins (Fig 1.23); body color yellow, brown or black. . . . . . . . . . . . . . . . . . . . 8
8. Fore femora with a ventral row of long bristles (Fig 1.24); cubitoanal crossvein of forewing usually touching, or very near anal cell (Fig 1.25); thorax often with branched gill vestiges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Perlidae
Fore femora without ventral row of bristles (Fig 1.26); cubitoanal crossvein of forewing, if present, distant from anal cell by more than its length (Fig 1.27); thorax without branched gill vestiges, but fingerlike gills sometimes present on thorax or submentum . . . . . . . . . . Perlodidae
Another Key to the Families of Ohio Stonefly Adults
1. Labium with glossae and paraglossae of approximately equal length (Fig 1.28). . . . . . . . . . . . . . . . . . . 2
Labium with glossae much shorter than paraglossae (Fig 1.29). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2. Basal segment of tarsus less than half the length of apical segment; sides of thorax with remnants of gills (Fig 1.30). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Basal segment of tarsus more than half the length of apical (Fig 1.31); thorax without gill remnants. . . . 4
3. Gill remnants present on first 2 or 3 abdominal segments; 3 ocelli. . . . . . . . . . . . . . . . . Pteronarcyidae
Abdomen without gill remnants; 2 ocelli. . . . . . . . . . . . . . . . . . . . Peltoperlidae, Peltoperla arcuata
4. Tarsus with second segment much shorter than first (Fig 1.34). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Tarsus with first and second segments subequal (Fig 1.35). . . . . . . . . . . . . . . . . . . . . .Taeniopterygidae
5. Cerci with 1 segment (Fig 1.36). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Cerci with at least 4 segments (Fig 1.37). . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Capniidae
6. Wings flat over dorsum at rest; labial palp with apical segment globular, much larger than basal segments (Fig 1.38). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Nemouridae
Wings at rest rolled down around sides of abdomen; labial palps with apical and preapical segments subequal (Fig 1.39). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Leuctridae
7. Thoracic sterna or pleura with profusely branced gill remnants at corners (Fig 1.40); forewing with cubitoanal crossvein intersecting anal cell or distad from it by no more than its own length (Fig 1.41). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Perlidae
Thoracic segments without gills or with unbranched, straplike gills; forewing with cubitoanal crossvein distand from anal cell by its own length or more or absent (Fig 1.43). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
8. Forewing with veins 2A and 3A arising from anal cell separately (Fig 1.43); gill remnants sometimes present on thorax or abdomen. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Perlodidae
Forewing with veins 2A and 3A arising from anal cell as single vein (Fig 1.44); gill remnants absent. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Chloroperlidae
Keys to the Families of Ohio Stonefly Adults
