Redescriptions of Monosertum parinum (Dujardin, 1845) and M. mariae (Mettrick, 1958) n. comb. from European passerine birds, with an amended generic diagnosis of Monosertum Bona, 1994 (Cestoda: Dilepididae).

The type-species of Monosertum Bona, 1994, M. parinum (Dujardin, 1845), is redescribed on the basis of the neotype designated by Bona (1994). M. mariae (Mettrick, 1958) n. comb. (originally Paricterotaenia mariae Mettrick, 1958) is recorded and redescribed from Erithacus rubecula L. (Passeriformes: Turdidae) in the Kaliningradskaya Oblast', Russia (new geographical record). An amended generic diagnosis of Monosertum is presented.