lamia

noun

1. Class. Myth. any of a class of monsters, half woman and half serpent, supposed to lure people, esp. children, in order to suck their blood
2. a vampire; female demon; sorceress

Etymology: ME lamya < L lamia < Gr; akin to lamos, abyss < IE base *lem-, with gaping mouth > L lemures, ghost (see lemur), Welsh llef, voice