They are said to have lived in a cave on Mt Dicte on the island of Thrace and had the role to sinning those who sinned against the gods.
Other artists had different ideas. The Harpies shown here appear to be young girls though the position and shape of the wings suggest that maybe young boy dancers in costume for a play are being depicted? Also there are 3 Harpies not two.
Their older sister was Iris goddess of the rainbow and messenger of the gods in the oldest epics.