lamia

lamia A monster preying upon human beings and who sucked the blood of children, often described as having the head and breasts of a woman and the lower half of a serpent.
(RQ:RBrtn AntmyMlncl), III.2.1.i:

Apollonius … by some probable conjectures, found her out to be a serpent, a lamia, and that all her furniture was like Tantalus' gold described by Homer, no substance, but mere illusions.