The Mongolian Species Of Isoperlinae (Plecoptera: Perlodidae) Author Zwick, P Author Surenkhorloo, P text Acta Zoologica Academiae Scientiarum Hungaricae 2005 2005-10-31 51 3 253 276 journal article 10.5281/zenodo.12586261 2064-2474 12586261 Isoperla eximia ZAPEKINA-DULKEIT , 1975 ( Figs 6b, c ) Isoperla eximia ZAPEKINA-DULKEIT , 1975: 211 , figs 14–19. Material studied. MONGOLIA , Selenge aimak , Mandal sum, Khonin nuga: Bar-Chuluut River ( 48°58’N , 106°59’E ), tributary of Eroo River , 1 f, 21.VIII.2001 ; 13 mm , 1 f, 04.VIII.2003 ; [ 49°02’N , 106°58’E ] 2 mm , 05/ 06.VIII.2003 ; Uram River , tributary of Khongi River , 1 m , 22.VII.2001 ; Ataa River , tributary of Sharlan River , 9 mm , 1 f, 30.VII.2003 (all leg. P. SURENKHORLOO ). A sibling of I. altaica with which it occurs sympatrically. Our specimens were identified by comparison with an illustration of the genitalia of the male holotype (from Bargusinskyi Reserve , Birikan River , 4.08.1972 , leg. V . A. BELYAEVA ; in ZIAS ) kindly provided by Dr V . TESLENKO . I. eximia is macropterous. It differs from I. altaica by the central field of the pterothoracic scuta distinctly paler than the lateral parts. The head has a small pale mark on the occiput and a dark shade in front of the pale frontoclypeal mark, but lacks tranverse marks connecting the eyes. Size. Fore wing length, mm 10.0– 10.2 mm , ff slightly larger. The penial sclerite is of the same general form as in I. altaica , but the base is not strikingly wider than the apex and not distinctly crested. Fig. 6. Isoperla altaica ŠÁMAL (a) and I. eximia ZAPEKINA-DULKEIT (b, c). Penis sclerites (a, b; to same scale) and fore body (c; not to scale) Egg. Similar to eggs of Mongolian I. altaica .