1. Ninth abdominal sternum much larger than 8; paraprocts or hemiterga developed into schlerotized hooks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Males, 2
Ninth abdominal sternum subequal to, of smaller than 8; paraprocts poorly sclerotized, hemiterga absent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Females, 9
2. Paraprocts sclerotized and recurved over apex of abdomen; hemiterga absent . . . . . . . . . . . . 3
Paraprocts unsclerotized; hemiterga well developed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
3. Hammer absent from sternum 9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Perlesta
Hammer present on sternum 9 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
4. Hammer elevated in lateral aspect; 3 occelli; tergum 10 with irregular transverse row of sensilla basiconica . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Eccoptura xanthenes
Hammer a low callus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
5. Forewing with crosveins between A1 and A2; aedeagus with paired lateral sclerites . .Perlinella
Forewing anal area without crossveins; aedeagus without paired lateral schlerites . . . . . . . . .6
6. Abdominal terga 9 and 10 without sensilla basiconica patches; aedeagus armed with thick patches of red-brown bristle-like spines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Acroneuria
Abdominal terga 9 and 10 without sensilla basiconica patches; aedeagus without bristle-like spines. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Attaneuria ruralis (may no longer be in Ohio)
7. Two ocelli . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Neoperla
Three ocelli . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
8. Hemiterga massive, extending to anterior margin of tergum 8; thoracic sterna with transverse bands of dark pigment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Agnetina
Hemiterga reaching, at most, middle of tergum 9; thoracic sterna without dark pigment bands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Paragnetina media
9. Females. Two ocelli . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10
Three ocelli . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
10. Subgenital plate unproduced, or a slightly produced, truncate, rounded or emarginated tab; forewing without crossveins between A1 and A2 . . . . . . . . . . . . . . . . . . . . . . . . . . .Neoperla
Subgenital plate slightly produced and broadly bilobed; forewing with crossveins between A1 and A2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Perlinella (in part)
11. Forewing with crossveins between A1 and A2 . . . . . . . . . . . . . . . . . . . . .Perlinella (in part)
Forewing without crossveins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
12. Subgenital plate with a transverse mesal tubercle; reticulation of egg chorion interrupted by smooth eclosion lines near each end . . . . . . . . . Attaneuria ruralis (may no longer be in Ohio)
Subgenital plate without transverse tubercle; egg chorion with, at most, a single eclosion line . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13
13. Subgenital plate notched . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Subgenital plate truncate or entire . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
14. Subgenital plate reaches at least midpoint of sternum 9 . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Subgenital plate covers 1/3 or less of sternum 9 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
15. Fully pigmented body color yellow to yellow-brown; vagina without sclerites or pigmented setal lining. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Eccoptura xanthenes
Fully pigmented body color brown to black; vagina lined with pigmented setae . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Acroneuria (in part)
16. Forewing length less than 14 mm; vagina with out pigmented setal lining . . . . . . . . . .Perlesta
Forewing length at least 15 mm; vagina with brown setal lining . . . . . . . . . . . . . . . . . . 17
17. Egg collar stalked; posterolateral vaginal accessory gland present . . . . . . Paragnetina media
Egg collar button-like, or absent; posterolateral vaginal accessory glands absent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Acroneuria (in part)
18. Thoracic sterna with transverse bands of dark pigment . . . . . . . . . . . . . . . . . . . . Agnetina
Thoracic sterna without transverse bands of dark pigment. . . . . . . . . . . .Acroneuria (in part)
Key to the Adult Perlidae of Ohio