3541 Author Judson, Sarah W. Author Nelson, C. Riley text Zootaxa 2012 2012-11-06 3541 1 118 journal article 1175­5334 505937B0-9F57-4068-82E6-8553826DD5AA Arcynopteryx polaris (Klapalek, 1912) SYNONYMY Arcynopteryx dichroa polaris Klapálek, 1912 Arcynopteryx altaica Zapekina-Dulkeit, 1957 Arcynopteryx dichroa Illies, 1966 Arcynopteryx polaris Zhiltzova, 1995 TYPE LOCALITY: USSR: Bykow, Lena-mudung. DIAGNOSIS: Males of A. polaris are often brachypterous ( Fig. 252 ), while females are macropterous. The male hemitergal lobes are slender and fingerlike ( Fig. 253 ). The lobes are straight and directed medially until the apices nearly touch above the epiproct. In contrast, the lobes of A. compacta are curved anteriorly ( Fig. 248 ) and those of A. sajanensis ( Fig. 258 ) are short and blunt. Female subgenital plate has a broad, shallow median notch and short lobes ( Fig. 254 ). The plate has rounded edges, can be circumscribed by a circle and is not sloped ( Fig. 249 ) or parallel sided ( Fig. 259 ) as in A. compacta and A. sajanensis respectively. Nymphs ( Fig. 255 ) are diagnosed by a darker overall appearance and less pronounced M-line on the clypeus, but is otherwise similar to A. compacta and Skwala pusilla ( Fig. 294 ). DISTRIBUTION—Global: East Palearctic- Regional: AOB, IDB— Aimag: AR^, BO^, BU^, KhD^, KhG, TO, UV*, ZA. DISCUSSION: This species was first documented in Mongolia by Zhiltzova (1975) who later revised the species group (Zhiltzova 1995). Many historical specimens that we examined were misidentifed as A. altaica , a previous synonym of A. polaris . Our scrutiny of the synonym of A. polaris aided the Plecoptera Species File (DeWalt, Neu-Becker & Steuber 2010) in accurately updating records concerning taxonomy of this group.