Porthesaroa brunea is a moth of the Lymantriidae family. It is found in central Madagascar. The male of this species has a wingspan of 20-24mm, head, front and palpae are yellow, antennae brownish and pectinated. Forewings are darkbrown, hidewings chocolate brown, underside of the wings is chocolate brown. The holotype of this species had been found central Madagascar at altitude of 1200m.