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 Megarcys DIAGNOSIS: Adults and nymphs have fingerlike thoracic gills, in addition to the submental gills ( Fig. 233 ) which many Perlodinae possess. The male hemitergal processes ( Fig. 279 ) are curved anteriorly, extending across tergite 9, and are longer than those in Arcynopteryx and Skwala . Males have a prominent epiproct with lateral stylets ( Fig. 279 ) which all other Mongolian Perlodinae lack. The female subgenital plate has a deep, narrow notch ( Fig. 280 ). DISTRIBUTION—Global: Amphi-Pacific— Regional: AOB, IDB— Aimag: BU^, KhG^, SE, TO.