1. Highly branched gills present on sides and venter of all thoracic segments (Fig 2.1) . . . . . . . . . . . 2
Gills absent, or restricted to cervical coxal area or fingerlike without numerous filaments (Fig. 2.2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Gill tufts present on abdominal sterna 1-2, habitus large, dark, gill-bellied (Fig. 2.3) . Pteronarcyidae
Gill tufts absent from abdominal sterna 1-2 (Fig. 2.1), habitus patterned, coxal-gilled . . . . . Perlidae
3. Coxae with single, telescoping gills [arising from ventral surface] (Fig 2.4), or abdomen with large triangular ventroapical plate; basal and second tarsal segments subequal in length (Fig 2.5), habitus swept-winged with long abdomen (Fig 2.6) . . . . . . . . . . . . . . . . . . . . . . . . . . . .Taeniopterygidae
Coxal gills [supracoxal gills may be present, but not telescopic] and ventroapical abdominal plates absent (Fig 2.2); second tarsal segment wedge-shaped and shorter than basal segment (Fig 2.7) . . 4
4. Thoracic sterna plates shieldlike, overlapping succeeding segment and typically fringed with
posterior setal row; habitus roach-like (Fig 2.8) . . . . . . . . . . . . . Peltoperlidae, Peltoperla arcuata
Thoracic sterna not shieldlike or overlapping, and without posterior setal row; habitus not roachlike. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
5. Apex of labial palps extending little beyond anterior paraglossa margin; paraglossa and glossa
extending forward about the same distance (Fig 2.9) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Entire apical segment of labial palp extending beyond anterior margin of paraglossa, paraglossa
longer than glossa (Fig 2.10) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
6. Metathoracic wingpads strongly diverging from body axis (Fig 2.11); cervical gills sometimes present (Fig 2.12); body form short and robust; extended hindlegs reaching approximately to abdominal apex; habitus swept-winged with short abdomen . . . . . . . . . . . . . . . . . . . . . . . . . . . .Nemouridae
Metathoracic wingpads essentially parallel to body axis (Fig 2.13); cervical gills absent; body form slender and elongate; extended hindlegs reaching far short of abdominal apex; habitus slender,
elongate non-gilled . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
7. Postmentum small, not covering bases of lacinia (Fig 2.14); membranous pleural folds along Ab1-9 (Fig 2.15); abdominal terga widest posteriorly and with posterior setal fringe; metathoracic wingpads about as wide as long, reduced or absent (Fig 2.16) . . . . . . . . . . . . . . . . . . . . . . . . . . .Capniidae
Postmentum large, partially covering bases of lacinia (Fig 2.17); membranous pleural folds not extending beyond Ab4 or Ab7 (Fig 2.18); abdominal segments essentially parallel-sided; terga of some genera without posterior dorsal setal fringe; metathoracic wingpads usually longer than wide and contained within mesothorasic wingpads (Fig 2.19) . . . . . . . . . . . . . . . . . . . . . . . .Leuctridae
8. Cerci three fourths or less abdominal length (Fig 2.20); apical maxillary palp segment small and typically set asymmetrically on penultimate segment (Fig 2.21); thoracic nota usually without pigmented pattern (Fig 2.20); metathoracic wingpads weakly diverging from body axis; habitus short-tailed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Chloroperliae
Cerci equal to, or longer than abdomen (Fig.2.22); apical maxillary palp segment subequal in length to penultimate segment and symmetrical (Fig 2.23); thoracic nota typically with contrasting light and dark pigmented pattern; metathoracic wingpads strongly diverging from body axis (Fig 2.22); habitus patterned, non-gilled or gilled . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Perlodidae
Simple Keys to Families of Ohio Stone Fly Nymphs
(From Stark, Szczytko & Nelson, 1998)
Also see Pictorial Key to Nymph Families
1. Tufts of highly branched gills on thorax around leg bases (Fig 2.1) . . . . . . . . . . . . . . . . . . . . . . . 2
Thorax without highly branched gills, single or forked gills present or absent (Fig 2.2) . . . . . . . . . .3
2. Abdominal apex rounded . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Perlidae
Abdominal apex long and spine-like . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Pteronarcyidae
3. Body wide and roach-like; head oriented downward. . . . . . . . . . . . . . . . . . . . . . . . . Peltoperlidae
There is only one species in Ohio . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Peltoperla arcuata
Body slender, not roach-like; head oriented forward . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
4. Hind wingpads project parallel to body axis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Hind wingpads project away from body axis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
5. Inner margins of hind wingpads continuous, notch between wingpads triangular. . . . Chloroperlidae
Inner margins of hind wingpads separated basally, notch between wingpads quadrangular . . . . . . 6
6. Hind wingpad longer than its greatest width; abdominal segments 8 and 9 undivided by
ventrolateral membranous bands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Leuctridae
Hind wingpad length equal to or shorter than its greatest width; abdominal segments 8 and 9
divided by ventrolateral bands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Capniidae
7. Mid tarsal segment small and wedge shaped . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Mid tarsal segment about as long as basal segment . . . . . . . . . . . . . . . . . . . . . . . Taeniopterygidae
8. Head and abdomen without distinctive pigment pattern;
body typically less than 10 mm long . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Nemouridae
Head and abdomen distinctively pigmented; body length up to 40 mm . . . . . . . . . . . . . . Perlodidae
Another Key to Families of Ohio Stone Fly Nymphs
(Modified from Whitfield and Purcell III (2013))
1. Abdomen with tufts of branched gills present on first 2 or 3 abdoinal segments . . . . .Pteronarcyidae
Abdomen without gills . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Thorax with sternites produced posteriorly and overlapping; head flattened; body cockroachlike . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Peltoperlidae
Thorax with overlapping sternites; head not flattened; body not cockroachlike . . . . . . . . . . . . . . 3
3. Labium with glossae and paraglossae about equal in length; dorsal surface of body usually unpatterned . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Labium with glossae much shorter than paraglossae; dorsum usually patterned . . . . . . . . . . . . . 7
4. Hind legs extending beyond abdominal apex; wing pads parallel to longitudinal body axis . . . . . . 5
Hind legs not extendiing as far as abdomina apex; wing pads parallel to longitudinal body axis . . 6
5. Tarsus with first and second segments subequal . . . . . . . . . . . . . . . . . . . . . . . . . Taeniopterygidae
Tarsus with second segment much shorter than first . . . . . . . . . . . . . . . . . . . . . . . . . Nemouridae
6. Abdominal segments 8 and 9 annular, without membranous ventrolateral fold separating tergal and sternal regions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Leuctridae
Abdonimal segments 8 and 9 with membranous folds separating tergal and sternal regions (as in anterior segments) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Capniidae
7. Thorax with branched gills ventrally and laterally . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Perlidae
Throax without branched gills . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
8. Cerci at least as long as abdomen; dorsum usually patterened . . . . . . . . . . . . . . . . . . . . Perlodidae
Cerci less than three-forths the length of abdomen; dorsum seldom patterned . . . . . . Chloroperlidae
Key to the Families of Ohio Stonefly Nymphs
