The strix was a persistent feature of the folklore of the Roman world and subsequently that of the Latin West and the Greek East. She was a woman that flew by night, either in an owl-like form or in the form of a projected soul, in order to penetrate homes by surreptitious means and thereby devour, blight or steal the new-born babies within them. The motif-set of the ideal narrative of a strix attack - the 'strix-paradigm' - is reconstructed from Ovid, Petronius, John Damascene and other sources, and the paradigm's impact is traced upon the typically gruesome representation of witches in Latin literature. The concept of the strix is contextualised against the longue-durée notion of the child-killing demon, which is found already in the ancient Near East, and shown to retain a currency still as informing the projection of the vampire in Victorian fiction.