The Greek Myth of Timandra & Bulis:
Timandra was the mother of Neophron. Neophron learned that his mother was having a love affair with his friend Aegypius, who was his age. Distressed at this, he thought of a way to end it. He made overtures to Bulis, Aegypius' mother, who though married, consented to be his lover. Having spied on his mother and his friend, Neophron knew the exact time of their frequent meetings and contrived to place Bulis in bed in the dark chamber. He told her he would be with her shortly, then detained his own mother on some kind of pretext. Soon Aegypius joined his mother in bed and coupled with her, suspecting nothing at all. They fell asleep, but Bulis awakened to find her son beside her. She took a dagger and dug out his eyes, then plunged it into her bosom. Apollo restored Aegypius' vision long enough for him to realize what had happened and thereupon changed all four of them into birds. The men became vultures, Timandra a sparrow-hawk, and Bulis a long-beaked bird that pecks out the eyes of fish.
-- Women of Classical Mythology, p. 425.