Lamia was the daughter of Poseidon and Libya, but the name is best known for the bogeywoman (with the face and breasts of a woman and the body of a serpent) who had been deformed by Hera and in revenge lured strangers so that she could devour them. (Some mythologists equate both Lamias.)
Her name is traditionally held to derive from laimos, 'throat', 'gullet', which would certainly be appropriate. However, there could also be a link with lamyros, 'voracious', 'gluttonous'. Perhaps the influence of both words is present in the name.