Elachista filiphila Wikipedia
Elachista filiphila is a moth of the Elachistidae family. It is found along the southern coast of Western Australia.
The wingspan is 8.8–9.2 millimetres (0.35–0.36 in) for males and 8.6 millimetres (0.34 in) for females. The forewings are bluish grey. The hindwings are grey.
The larvae feed on an unidentified Cyperaceae species. They mine the culms of their host plant. The mine starts as a narrow gallery which is directed straight upward. Later it turns downward, first under the epidermis, broadening until the whole stem is hollow. Pupation takes place outside of the mine.