Five species of acanthocephalans of the family Centrorhynchidae are recorded from birds in Bulgaria: Centrorhynchus amphihius Das, 1950 from Buteo buteo (L.) (new host record), C. glohocaudatus (Zeder. 1800) Luhe, 1911 from Falco tin-nunculus L. and F. vespertinus L, (new host record), Sphaerimstris picae (Rudolphi, 1819) Golvan, 1960 from Pica pica (L.) and Lanius excuhitor L. (new host record), S. lancea (Westrumb, 1821) Golvan, 1960 from Vanellus vanellus (L.), and S. turili (Yamaguti, 1939) Golvan, 1960 from Turdus merula L„ Cinclus cinclus (L.) (new host record) and Stumus vulgaris L. (new host record). New geographical record for Europe is this of C. amphihius, and for Bulgaria - this of S. lurdi. The species are described and figured on the basis of Bulgarian specimens. Sphaerimstris picae is recognized as a valid species and S. teres is considered its synonym. A male of S. picae with a copulatory cap is reported.
The syntypes of Deltokeras omitheios Meggitt, 1927 (the type-species of Deltokeras Meggitt, 1927), a parasite of Urocissa erythrorhyncha (Passeriformes, Corvidae) in South Asia, are redescribed. Deltokeras is considered a monotypie genus. An amended generic diagnosis is presented.