E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
Peacocks Feather Unlucky (A).
The peacocks tail is emblem of an Evil Eye, or an ever-vigilant traitor. The tale is this: Argus was the chief Minister of Osris, King of Egypt. When the king started on his Indian expedition, he left his queen, Isis, regent, and Argus was to be her chief adviser. Argus, with one hundred spies (called eyes), soon made himself so powerful and formidable that he shut up the queen-regent in a strong castle, and proclaimed himself king. Mercury marched against him, took him prisoner, and cut off his head; whereupon Juno metamorphosed Argus into a peacock, and set his eyes in its tale.