When Procne discovered her sister and her gruesome fate, she took revenge against her husband by murdering their only child, a young boy named Itys.

[10] Philomela, unable to speak or escape her prison, wove in letters in her tapestry or a gown, that spoke of her fate at the hands of Tereus, and sent it to Procne.

Once Procne got hands on her tapestry, she disguised herself in bacchic attire, joined the festivities with the other women, and located the cabin in which Philomela was kept captive.

And then while he is calling out and seeking him, Philomela, springs forward, her hair wet with the dew of that frenzied murder, and hurls the bloodstained head of Itys in his father’s face.

[18] A late antiquity scholiast, Pseudo-Nonnus, names Zeus specifically as the god who put an end to the chase by transforming them all into birds.

[19] The Byzantine scholar Eustathius of Thessalonica swapped the roles of the two sisters, so that Procne is the unmarried woman who was raped and mutilated by Tereus.

[20] One author has Tereus succeed in murdering both Procne and Philomela before they are all transformed into birds, but hoopoes continued to chase swallows and nightingales.

[22][23] Once Chelidon reveals to Aëdon what has happened, the myth proceeds as above, with the difference that the two women manage to reach their father (who is Pandareus here) who has his servants beat and tie up Polytechnus, and then smeared with honey and left to the mercy of insects.

[25] As later authors on Homer would clarify and expand, Aëdon the wife of King Zethus killed her son accidentally while trying to kill another boy, Amaleus, the son of her sister-in-law Niobe (the wife of Zethus's twin brother Amphion), envious of Niobe's vast progeny when she had born only one child.

[28] Jennifer Marsh has argued that Sophocles was inspired by Euripides's play Medea, a work where a woman murders her children in order to enact revenge against her husband, and subsequently it was him who introduced the element of infanticide and child-eating in Procne's story.

[32] Earlier than Sophocles, a seventh century BC metope from a temple of Apollo seem to attest to the notion of the nightingale and the swallow being partners of Itys/Itylus's[b] murder, with Aëdon/Procne as the main culprit.

[33] The swallow genera Progne, Ptyonoprogne and Psalidoprocne and the treeswift family Hemiprocnidae derive their names from the myth of this Thracian queen.