Aegeria or Egeria
One of the Camenae in Roman mythology, from whom, according to the legends of early Roman story, Numa received his instructions respecting the forms of worship which he introduced. The grove in which the king had his interviews with the goddess, and in which a well gushed forth from a dark recess, was dedicated by him to the Camenae. (Livius i)
The Roman legends, however, point out two distinct places sacred to Aegeria, one near Aricia (Virgil's Aeneid; Fasti By Ovid), and the other near the city of Rome at the Porta Capena, in the valley now called Caparella, where the sacred shield had fallen from heaven, and where Numa was likewise believed to have had interviews with his beloved Camena.
Ovid (Metamorphoses) relates that, after the death of Numa, Aegeria fled into the shady grove in the vale of Aricia, and there disturbed by her lamentations the worship of Diana which had been brought thither from Tauris by Orestes, or, according to others, by Hippolytus. Virgil (Aeneid vii) makes Hippolytus and Aegeria the parents of Virbius, who was undoubtedly a native Italian hero.
This is one of the most remarkable instances of the manner in which the worship of a Greek divinity or hero was engrafted upon and combined with a purely Italian worship. Aegeria was regarded as a prophetic divinity, and also as the giver of life, whence she was invoked by pregnant women.
From Smith's Dictionary of Greek and Roman Biography and Mythology