In favour of the Isiac reading of the fr. 191 B. of Varro’s Menippean Satires, which Lucian Müller suggested without argumentation and which has not gained a wide recognition, it is possible to mention parallel citations, in particular from Book XI of the Metamorphoses by Apuleius. I propose that the fragment could read like Varro’s polemic against the great popularity with the Roman matrons of nocturnal initiations in honour of Isis, which were commonly regarded as of doubtful morality.