Apollodorus gives Echidna a career and a death; for her shape he needs his editor. The served chapter makes her “daughter of Tartarus and Earth”, a predator “who used to carry off passers-by, was caught asleep and slain by Argus” — the ambusher taken by ambush [The Library (Bibliotheca), BOOK II, ch. I]. What makes her this motif — the hybrid body — enters that page only as Frazer’s marginal pointer to “the monster Echidna, half woman, half snake” in Hesiod [ibid., editor’s note]. The pointer lands on our own shelf. The served Theogony gives the body itself: “half a nymph with glancing eyes and fair cheeks” and “half again a huge snake, great and awful, with speckled skin”, housed in a hollow cave, “a nymph who dies not nor grows old all her days” [Hesiod, the Homeric Hymns, and Homerica, THE THEOGONY]. The two witnesses sit unreconciled — the genealogist kills what the theogonist calls deathless — and her brood, Cerberus and “the evil-minded Hydra of Lerna”, populates neighboring addresses in this index [ibid.]. The citation lane supplied only the Apollodorus page; the Hesiod half was reached by following the editor’s note and verified by reading.