From The Art and Popular Culture Encyclopedia
In ancient Greek mythology, Lamia (Greek: Λάμια) was a beautiful queen of Libya who became a child-eating daemon. While the word lamia literally means large shark in Greek, Aristophanes claimed her name derived from the Greek word for gullet (laimos), referring to her habit of devouring children. (Aristophanes, The Wasps, 1177.)
Some accounts say she has a serpent's tail below the waist. This popular description of her is largely due to Lamia, a poem by John Keats published in 1819. However, Diodorus Siculus describes her as having nothing more than a distorted face.