In this study, we describe a new species of the genus Erechthias from East Asia. Specimens collected in Japan and China were examined based on adult morphology and DNA sequence data to clarify its taxonomic status and additional observations were conducted to clarify its biology. Adults resemble E. iolaxa and E. minuscula but can be distinguished by differences in the forewing pattern and genital morphology. DNA analyses revealed low intraspecific genetic variation and clear genetic divergence from closely related species. The larvae feed on various types of dead plant material, including fruits, galls, and dead stems. Photographs of the male and female adults, wing venation, genitalia, and larvae are provided.
