Nagiella tristalis Matsui & Naka, sp. nov. is described from Japan, based on DNA barcoding and morphological evidence. The two species previously known from Japan, N. quadrimaculalis and N. inferior, are diagnosed. Photographs of adults, including male and female genitalia of the three species, are provided.
Keywords: Patania; Pleuroptya; DNA barcodes; Rubus buergeri; genitalia.
Yuki Matsui, Hideshi Naka, Utsugi Jinbo.