Lémures, murum, f. g. pl. nu. Spirits which do walk by night with horrible figures.
Lewis and Short: Latin dictionary
Lĕmŭres, um, m., shades, ghosts of the departed. I.Lit.: Lemures animas dixere silentum, Ov. F. 5, 483.—B.Transf., in gen., ghosts, spectres: lemures larvae nocturnae et terrificationes imaginum et bestiarum, Non. 135, 15 sq.: somnia, terrores magicos, miracula, sagas, Nocturnos lemures portentaque Thessala rides, Hor. Ep. 2, 2, 209: tunc nigri lemures ovoque pericula rupto, Pers. 5, 185.—Hence, II. Lĕmū-rĭa, ōrum, n., a festival held on the 9th, 11th, and 13th of May to appease the ghosts of the departed: nocturna, Ov. F. 5, 421 sq.