According to Diodorus Siculus, Lamia was born the beautiful daughter of King Belus of Egypt, making her the granddaughter of Poseidon and Lybie.[7] Upon her father's death she became queen of one of his territories, Libya.[8] However, while visiting Delphi, Pausanias remarks that Lamia was the daughter of Poseidon. He also states that Lamia and Zeus were the parents of Herophile, a noted sibyl.
Diodorus goes on to relate that Lamia had an affair with Zeus and bore him children. When Hera, Zeus's wife, discovered the affair, she became enraged and killed the children. Driven insane with grief, Lamia began devouring other children, and, according to Diodorus, her face became hideously distorted from her grisly deeds.[9]
Zeus then gave her the ability to remove her eyes. In Diodorus the purpose of this is unclear, but other versions state this came with the gift of prophecy. Zeus did this to appease Lamia in her grief over the loss of her children.[10]
Later stories state that Lamia was cursed with the inability to close her eyes so that she would always obsess over the image of her dead children. Some accounts (such as that of Horace, below) say that Hera forced Lamia to devour her own children. Myths variously describe Lamia's monstrous (occasionally serpentine) appearance as a result of either Hera's wrath, the pain of grief, the madness that drove her to murder, or - in some rare versions - a natural result of being Hecate's daughter.[11]
Horace, in Ars Poetica (l.340) imagines the impossibility of retrieving the living children she has eaten:
Neu pranse Lamiae vivum puerum extrabat alvo.
Alexander Pope translates the line:
Shall Lamia in our sight her sons devour,
and give them back alive the self-same hour?
Stesichorus identifies Lamia as the mother of Scylla, by Phorcys.[12] This may be a conflation of Lamia with the sea goddess Ceto, traditionally Phorcys's wife and mother of Scylla. Further passing references to Lamia were made by Strabo (i.II.

and Aristotle (Ethics vii.5). Other sources cite Triton as having fathered Scylla by Lamia.
Antoninus Liberalis identifies the dragon Sybaris with Lamia, another conflation.