Ostrocerca complexa

3. Ostrocerca complexa (Claassen, 1937)

Notched Forestfly

http://lsid.speciesfile.org/urn:lsid: Plecoptera.speciesfile.org:TaxonName:6144

(Figs. 25–30)

Nemoura complexa Claassen, 1937:43. Holotype male (Cornell University Insect Collection), Artists Brook, Essex Co., New York, USA

Nemoura complexa: Claassen, 1940:53

Nemoura (Ostrocerca) complexa: Ricker, 1952:40

Ostrocerca complexa: Illies, 1966:217

Ostrocerca complexa: Zwick, 1973:344

Nemoura (Ostrocerca) complexa: Hitchcock, 1974:97

Ostrocerca complexa: Young et al., 1989:259

Distribution. Canada: NB, NS, ON, PQ. USA: CT, MA, MD, ME, NY, PA, VA, WV (DeWalt et al. 2022)

Male. Macropterous. Body length 4.1–5.8 mm, forewing length 5.5–6.6 mm (n = 27). Gills absent. Cerci enlarged and elongated, sclerotized, medially arcuate, and terminating in a bifurcated apex (Figs. 25–26). Paraprocts divided into a membranous outer lobe and a sclerotized inner lobe; inner lobe is C-shaped, apically divergent, and produced distally as a triangular projection (Fig. 22; Young et al. 1989, their fig. 6). Epiproct elongate and complex; dorsal sclerite is bifurcated apically, open distally with dark sclerotized longitudinal bands along the midline, and membranous laterally with several spine-like projections near the base and 3–4 dark spines apically (Figs. 26–27); ventral sclerite is membranous apically with open medial slot, sclerotized proximally, and with distinctive fork-like process that extends through the dorsal sclerites, bearing three short prongs, one proximally and two distally (Figs. 26–27).

Female. Macropterous. Body length 4.6–6.5 mm, forewing length 6.3–7.5 mm (n = 10). Gills absent. Cerci enlarged but unmodified (Fig. 29). The 8 th sternum is moderately enlarged as a subgenital plate, extending only partially over the 9 th sternum and distally concave; medial region is markedly sclerotized (Figs. 29–30). The 7 th sternum is modified distally as a large nipple-shaped process that extends at least over ¼ of the 8 th sternum (Figs. 29–30).

Larva. Undescribed.

Comments. Ostrocerca complexa is an Appalachian-distributed species known from Nova Scotia and New Brunswick south to Virginia and West Virginia (DeWalt et al. 2022). The females of O. complexa and O. prolongata are difficult to identify with certainty without associated males.