Apollo, cum Coronidem gravidam fecisset, corvum ei custodem apposuit, ne quis ad eam occulte temerator accederet. cum hac Lycus occulte concubuit, quem fulmine Iuppiter exstinxit. ipsam Coronidem Apollo sagittis occidit, cuius mortuae exsecto utero Aesculapium produxit in lucem. unde Vergilius: ‘fulmine poenigenam Stygias detrusit ad undas’ [Aen. 7.773], id est per poenam matris natum.
(Lactantius Placidus, Comm. in Stat. Theb. 3.506)
When Apollo had made Coronis pregnant, he assigned a raven as a guardian over her lest any rash person should secretly approach her. With her by stealth lay Lycus whom Jupiter destroyed with a thunderbolt. Coronis herself Apolo slew with his arrows; from her womb, cut open when she was dead, he brought forth Asclepius into the light of day. Wherefore Vergil says: ‘with his thunderbolt he [sc. Jupiter] hurled down to the Stygian waters ‘poenigenam’, that means him who was born through the punishment of his mother. (tr. Emma & Ludwig Edelstein)