A Tragic Thyestes? Pollux describes a stock tragic mask, the White Old Man: The white man's hair is entirely grey, and he has curls around the head, a firm chin, and jutting eyebrows and off-white complexion. The onkos is short.
We find this mask on a painted wall of the Third Style (ca. 80-20 B.C.) in the House of Julia Felix in Pompeii:
Image from: Jacqueline and Maurice Guillard. "Frescoes in the Time of Pompeii." First Americal Edition. New York: C.N. Potter, 1990. p. 157, p. 83.
This may be the mask for the Thyestes character, and the image Apulieus seeks to superimpose on the face of his principal accusor.