Brunia sarawaca is a moth of the Arctiidae family. It was described by Butler in 1877. It is found on Borneo, Peninsular Malaysia, Java and the north-eastern Himalayas. The habitat consists of lowland forests. The larvae feed on mosses or lichen growing on trees, but they have also been found on the leaves of Tamarindus and Eugenia species. They are densely covered with dark grey hairs. The head is yellow with two black spots. Pupation takes place in a dense cocoon.