1.        Transverse line of stout, socketed setae on occiput partial or complete, extending to             area of ecdysial suture (Fig. 2.1.1; Fig. 2.1.2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

            Transverse line of stout, socketed setae on occiput absent or confined to just medial of             compound eye (Fig. 2.1.3, Fig. 2.1.4) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

2.        Two ocelli (Fig 2.1.5) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Neoperla

            Three ocelli, some with small, obscure median ocellus (Fig 2.1.6) . . . . . . . . . . . . . . . 3

3.         Anal gills present (Fig. 2.1.7). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

            Anal gill absent (Fig. 2.1.8). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

4.         Row of socketed setae on occiput complete and tight row to ecdysal surture                         (Fig.2.1.9); abdomen and thorax not covered with heavy socketed setae (i.e., not             freckled)(Fig.2.1.10) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Agnetina

            Row of socketed setae on occiput incomplete, open in places, but reaching or nearly             so, ecdysal suture (Fig. 2.1.11); abdomen and sometimes thorax covered with heavy             socketed setae, giving the impression of a freckled surface (Fig. 2.1.12) . . . . . . . . . . .             . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Perlesta Group A

5.         Transverse line of stout, socketed setae on occiput somewhat wavy and broken at             midline; body uniformly light brown; head unicolorous; possibly extirpated from Ohio .             . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Attaneuria ruralis

            Transverse line of stout, socketed setae on occiput not wavy and not broken at midline             (Fig. 2.1.13); body either uniformly dark or patterned (Fig. 2.1.14); head often with 5             star-like light markings around median ocellus (Fig. 2.1.15) . . . . . . . . . . Paragnetina

6.         Marginal setae of lacinia stout and few, forming a distinct cluster below second tooth             (Fig. 2.1.16) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Perlesta Group B

            Marginal setae of lacinia many, may be stout, forming a near continuous line to the             base of lacinia (Fig. 2.1.17) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

7.         Femora and tibia with dorsal and ventral fringes of long, silky setae (Fig. 2.1.18);             habitus long and narrow to live between gravel spaces (Fig. 2.1.19) . . . . . . Perlinella

            Femora and tibia with only dorsal fringes of long, silky setae (Fig. 2.1.20); habitus             stout (Fig. 2.1.21) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

8.         Dorsum of head with large area of yellow pigment anterior to median ocellus
            (Fig 2.1.22) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Eccoptura xanthenes

            Dorsum of head mostly brown, frequently with a variable yellow M-shaped mark             anterior to median ocellus (Fig 2.1.23, Fig 2.1.24) . . . . . . . . . . . . . . . . . Acroneuria

 

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Stoneflies of Ohio

Key to the Genera of Ohio Perlidae Nymphs

(Modified from Stewart and Stark (2002), Hitchcock, 1974, and Poulton and Stewart, 1991)