Themisto

For the moon of Jupiter, see Themisto (moon).

In Greek mythology, Themisto was the third and last wife of Athamas. She had one son by him, Schoeneus.

When Athamus returned to his second wife, Ino, Themisto dressed all her own children in white clothing, and Ino's in black. Themisto then proceeded to kill all the black-clothed children, as an act of revenge against Athamus.

What Themisto did not realise was that Ino had switched the children's clothing, and so she in fact killed her own children (except, apparently, for Schoeneus).