Corymica arnearia is a moth of the family Geometridae. It is found in Japan, in Taiwan and from the Oriental Tropics to Sulawesi and Borneo. Adults have a clearly marked pale, red edged medial bar on the forewing dorsum and a corresponding narrow mark on the costa. There is also a red marginal mark on the forewing underside. The larvae feed on Cinnamomum camphora. They are bright green with a brown head.