Perlidae

Judson, Sarah W. & Nelson, C. Riley, 2012, 3541, Zootaxa 3541, pp. 1-118 : 35

Perlidae

COMMON NAME: Common Stoneflies.

SIZE: Large (20–50 mm).

FEEDING GROUP: Predators.

TOLERANCE VALUE: 1 (Low).

DIAGNOSIS: Adults are golden to yellow in color All perlids currently known from Mongolia belong to the subfamily Perlinae (Sivec, Stark & Uchida 1988) . Males of this subfamily have pronounced hemitergal processes, extensions of the 10th tergum, the shape ( Fig. 203, 225) and length of which are diagnostic for genera and some species. The female subgenital plate is variably shaped, either deeply notched or subtriangular. The relatively large nymphs are strikingly patterned ( Fig. 196, 198) and in this respect are superficially similar to Perlodidae nymphs. All 3 thoracic segments have finely branched gills ( Fig. 6). Gills are absent from abdominal segments 1–2 in Perlidae but present in Pteronarcyidae . As in other Systellognatha, the labium has a deep notch and the paraglossa extend beyond the glossa ( Fig. 8).

DISCUSSION: The nymphs of this family are found in streams and rivers of all sizes. They are often found under logs and stones and in snags where an abundance of prey can be found. The nymphs require 1–3 years to mature and as such, multiple instars with a wide range of sizes are often found when sampling.