Lewis & Short

Psylli, ōrum, m., = Ψύλλοι, an African people south-west of the Syrtis Major, celebrated as serpent-charmers: qui Psylli nominantur, Cels. 5, 27, 3; Plin. 7, 2, 2, § 14; 8, 25, 38, § 93; Suet. Aug. 17; Luc. 9, 893.
Sing.: exemplum Psylli secutus, Cels. 5, 27, 3.