was one of the delatores or informers in the time of Nero, and thus rose from poverty to great wealth. He was accused in the senate at the commencement of the reign of Vespasian, on which occasion he was defended by L. Vipstanus Messalla, who is described as his frater, whether his brother or cousin is uncertain (Tac. Hist. 4.42). Under Domitian he resumed his old trade, and became one of the instruments of that tyrant's cruelty. He survived Domitian, and is frequently spoken of by Pliny with the greatest detestation and contempt (Ep. 1.5, 2.10, 4.2, 6.2). Martial, on the contrary, who flattered all the creatures of Domitian, can scarcely find language strong enough to celebrate the virtues, the wisdom, and the eloquence of Regulus. (Ep. 1.13, 83, 112, 4.16.)