Smith 's Dictionary: MANTO (Mavrri). 1. A daughter of the Theban soothsayer Teiresias. She herself was a prophetess, first of the Ismenian Apollo at Thebes, where monuments of her existed (Paus. ix. 10. § 3), and subsequently of the Delphian and Clarian Apollo. After the taking of Thebes by the Epigoni, she, with other captives, was dedicated to Apollo at Delphi. The god sent the captives to Asia, where they founded the sanctuary of Apollo not far from the place where afterwards the town of Colophon was built. Rhacius, a Cretan, who had settled there before, married Manto, and be came by her the father of Mopsus. (Apollod. iii. 7. § 4 ; Paus. vii. 3. § 1, ix. 33. § 1 ; Strab. ix. p. 443 ; Schol. ad Apollon. i. 908.) According to Euripides, she had previously become the mother of Amphilochus and Tisiphone, by Alcmaeon, the-leader of the Epigoni. (Apollod. iii. 7. § 7.) Being a prophetess of Apollo, she is also called Daphne, i. e. the laurel virgin. (Diod. iv. 66 ; comp. Athen. vii. p. 298.)
Mantho is mentioned as one of the sibyls by Balthasar Porreflo, who wrote in Spain in 1621, "Besides these twelve already stated there are others mentioned, such as Mantho, Daphne daughter of Tiresias . . . Cassandra, Xeno-clea, Melisa and Lampusa, and Strabo in his Geography mentions many others" -- http://www.archive.org/stream/playofsibylcassa00kingrich/playofsibylcassa00kingrich_djvu.txt
Der Kleine Pauly: 1) The daughter of the seer Teiresias was Manto (without h), also called Daphne. She was a seer too and the mother of Mopsos. 2) In Verg. Aen. 10, 198 is mentioned a presaging nymph Manto, later mother of Ognus by the river-god Tiberis.
A mythological dictionary By Charles Kent, William Charles M. Kent: Sibyls. Certain renowned women inspired by heaven with prophecy and other celestial knowledge. They are generally regarded as numbering ten, residing usually in the following places : Persia, Libya, Delphi, Erythraea, Samos, Tiburtis, Cumae in ALolia, Ancyra in Phrygia, and Marpessa on the Hellespont. The most celebrated of all was the Cumsean Sibyl, variously called Amalthea, Demophile, Herophile, Daphne, Manto, Pheimonoe, and Deiphobe; she conducted Eneas to hell, and offered successively nine, six, and at last three prophetic volumes to Tarquin.
Pat Lawrence (Slokind on the discussion board) noted: Considering that mantikos means 'of prophetic utterance ' and manteia was both prophecy and an oracular shrine, it is not surprising that Mantô should be given as a name to a sibyl. Names in -ô are typically feminine.
A counterargument to the proposition that Daphne and Mantho are one and the same from http://www.goddess.org/vortices/notes/delphi.html.
Ovid makes Daphne the daughter of the river God Peneus, and the blunt (literally of Cupid 's revenge) Apollo chided Cupid one day for his use of the bow, and bragged how his arrow never failed, and how he slew Python with countless darts. Cupid countered by telling Apollo "You are far above all creatures living, and by just that distance your glory less than mine". Cupid then waited for his revenge. That was not long coming, when Cupid saw Apollo approaching the place where Daphne bathed in her father 's pool. He drew from his quiver two different arrows, one gleaming golden and sharp, the other deadeningly blunt, tipped with lead to drive all love away, and this he used on Daphne, while he shot Apollo with the stinging sharp arrow of love, through bone, through marrow, and through the heart, and he loved Daphne. Daphne had many suitors, bus spurned them and made the marriage torches hateful and criminal to her. Apollo pursued her, telling her he was lord of Delphi, Tenedos, Claros and Patara and Zeus was his father. But she fled and Apollo, driven by the superior power of love gave chase. She escaped him at first, but his relentless pursuit drove her to terror and exhaustion, and seeing the river of her father she cried for his help. Her father heard and "when her limbs grew numb and heavy, her soft breasts were closed with delicate bark, her hair was leaves, her arms were branches, and her speedy feet roots and held, and her head became a tree top. Everything gone except her grace, her shining. Apollo lover her still. He placed his hand where he had hoped and felt the heart still beating under the bark; and he embraced the branches as if they still were limbs, and kissed the wood, and the wood shrank from his kisses," and from that time on he loved the Laurel above all trees.
The truth of the matter is, Daphne (laurel) was the daughter of Teiresias, the blind Theban Prophet who gave birth to her during the seven years when he had been a woman. His other daughter, Manto [the mother of Mopsus, the seer] he sired after he was a man again. Daphne and Manto were both taken captive when Thebes fell in the generation before Troy. Manto was sent to Ionia where she married Rhacius, King of Caria, by whom she had Mopsus-said to be the son of Apollo. Daphne remained a virgin and was sent to Delphi; most likely to add the power of Teiresias to the Delphi oracle which had recently (within 100 years) been taken over by the Apollonians. There she became the Sibyl. There are some who say that Manto had her name changed to Daphne when she was sent to Delphi, but this is perpetrated by Apollonians who forget that the Sibyl spurned Apollo 's love, while Mopsus was the son of Apollo and Manto.