The wingspan is 32–34 mm (1.3–1.3 in). Adults are similar to Ethmia praeclara, but the forewings are broader, the black dots are larger and there are nine marginal dots. The hindwings are ochreous yellow.[3]
^Savela, Markku, ed. (September 4, 2019). "Ethmia argopa Meyrick, 1910". Lepidoptera and Some Other Life Forms. Retrieved August 29, 2020.
^Meyrick, E. (1910). "Descriptions of Malayan Micro-Lepidoptera". Transactions of the Entomological Society of London: 461. Retrieved 15 June 2020 – via Internet Archive. This article incorporates text from this source, which is in the public domain.