Eudonia axena is a moth in the Crambidae family. It was described by Meyrick in 1884. It is found in New Zealand. The wingspan is 19–26 mm. The forewings are variable in colour, but the markings are always of the same form. They are sometimes mixed with ochreous-greenish, or partially blackish. In males, the markings are suffused with blackish towards the costa. The hindwings of the males are pale grey, while they are ochreous posteriorly in females. Adults have been recorded on wing in March.