Poorly known species of stoneflies Isoperla pseudornata and Kaszabia nigricauda (Plecoptera, Perlodidae) from eastern Palaearctic

Descriptions of the previously unknown male of Isoperla pseudornata Zhiltzova and nymph of Kaszabia nigricauda (Navas) from the subfamily Perlodidae are given. Sternite VIII of I. pseudornata male without vesicle, posterior margin with stout and short brownish setae medially. Sternite IX forms subgenital plate. Everted aedeagus up curved, turned towards dorsum with two rounded lobes and one finger-like apical lobe ended by membranous shell-hole depressed medially. Aedeagus membrane covered with small sclerotized fine pointed spicules; spicules absent on the tip of shell-hole. Finger-like projection at the base and ventrally covered with sclerotized fine pointed spicules and rounded sclerotized formations. I. pseudornata differs from other eastern palaearctic species by spots on the head, pronotum, and abdominal tergites. Head of K. nigricauda nymph with large brown M-shaped spot, tapered along anterior margin by two thin bands expanded on frontoclypeus; interocular area with a small pale spot confluented with big transverse W-shaped spot on occiput. Lacinia narrowed to the tip, bidentate, tip of galea reaches the base of subapical tooth. Pronotum with medial, pale, crosshaped spot, lateral fields dark, lateral margins pale. Meso- and metanotum with complicated light pattern extended to the base of wing pads. Legs pale. Abdominal tergites brown, with transverse pale stripe widened laterally on the last tergites. Tergite X with large pale heart-shaped spot medially. Cerci with dorsal silky hair fringe; in the apical part, apical whorl of cerci with short setae; one ventral and one dorsal seta longer than the others; dorsal setae are longer than ventral ones.