"The Great Pan is Dead"

Epitherses ... said that designing a voyage to Italy, he embarked himself on a vessel well laden both with goods and passengers. About the evening the vessel was becalmed about the Isles Echinades, whereupon their ship drove with the tide till it was carried near the Isles of Paxi; when immediately a voice was heard by most of the passengers (who were then awake, and taking a cup after supper) calling unto one Thamus, and that with so loud a voice as made all the company amazed; which Thamus was a mariner of Egypt, whose name was scarcely known in the ship. He returned no answer to the first calls; but at the third he replied, Here! here! I am the man. Then the voice said aloud to him, When you are arrived at Palodes, take care to make it known that the God Pan is dead. Epitherses told us, this voice did much astonish all that heard it, and caused much arguing whether this voice was to be obeyed or slighted. Thamus, for his part, was resolved, if the wind permitted, to sail by the place without saying a word; but if the wind ceased and there ensued a calm, to speak and cry out as loud as he was able what he was enjoined. Being come to Palodes, there was no wind stirring, and the sea was as smooth as glass. Whereupon Thamus standing on the deck, with his face towards the land, uttered with a loud voice his message, saying, The great Pan is dead. He had no sooner said this, but they heard a dreadful noise, not only of one, but of several, who, to their thinking, groaned and lamented with a kind of astonishment. And there being many persons in the ship, an account of this was soon spread over Rome, which made Tiberius the Emperor send for Thamus; and he seemed to give such heed to what he told him, that he earnestly enquired who this Pan was; and the learned men about him gave in their judgments, that it was the son of Mercury by Penelope.

--Plutarch, Why the Oracles Cease to Give Answers
(R. Midgley, trans., 1870,
reprinted in R. Stoneman, A Literary Companion to Travel in Greece 25-6 (Penguin , 1984)

I have been trying to find out more about the great Pan and his story. So far, the best I can do is a the poem, On the Morning of Christ's Nativity by John Milton (1629). Stanza XIX reads:

The Oracles are dumb,
No voice or hideous hum

Runs through the arched roof in words deceiving.

Apollo from his shrine
Can no more divine

With hollow shriek the steep of Delphos leaving.

No nightly trance, or breathed spell,
Inspires the pale-ey'd Priest from the prophetic cell.

In his complete Milton, Merritt Y. Hughes says "Many details of the flight of the pagan gods seemed to A. S.Cook to come from the Apotheosis of Prudentius or the Parthenicae (III, i) of Mantuan." See M. Hughes, John Milton: Complete Poems and Major Prose 48 (1957). Are there other references?