Delias frater is a butterfly in the family Pieridae. It was described by Karl Jordan in 1911. It is found in New Guinea.
The wingspan is about 56 mm. Adults are similar to Delias eichhorni, but the white area on the upper surface of the forewings is smaller and more diffuse at the edges, and sometimes so much diffused with black as to be almost entirely suppressed. The black discocellular bar of the underside of the forewings is very thin and angulate, being sometimes almost interrupted before R2 (vein 5).[1]