Palaeomystella oligophaga is a moth of the Agonoxenidae family. It is found in Brazil. The length of the forewings is 7.7-10.1 mm. They have pale-brown scales tipped with brownintermixed with brown scales, The hindwings are pale gray. The larvae feed on Macairea radula and Macairea thyrsiflora. They create a prosoplasmatic histioid gall on their host plants. The species may create three different types of soft, fleshy galls. The larvae are pale gray and 5.2-8.7 mm long.