Well, I found a reference in Life in Ancient Rome, by F.R.Cowell (p.66) and in this text: https://www.academia.edu/5307780/Love_Out_of_Lust_Roman_Mirrors_as_Teaching_Aids_in_Love.
Much of Roman Religion was a vast expansion of a proto-Roman cult of the dead and the mirror was often used for necromantic and/or spiritualist purposes. The use of the mirror for these purposes was known as catopromancy.
See Daniel Ogden, 'Greek and Roman Necromancy' and Daniel Ogden, 'Night's Agents'
"The Moral Mirror of Roman Art" by Rabun Taylor is indeed an excellent work. I strongly recommend it. It also has a great list of bibliographical resources.