Abstract
Sixty six cestode specimens were obtained from the small intestines of a ground thrush, Trudus sibiricus, at Beppu City, Oita Prefecture, Southern Japan, on February 2, 1995. The specimens could be morphologically divided into 3 groups; the first group consisting of 35 specimens was identified as Sobolevitaenia turdi n. sp., the second of 26 specimens as S. oitaensis n. sp. and the third of 3 specimens as Neyraia turdi n. sp. S. turdi n. sp. closely resembles S. moldavica Shumilo and Spasskaja, 1975 but differs from it in the larger rostellum, the smaller number of rostellar hooks, and the larger rostellar sac. S. oitaensis n. sp. closely resembles S. moldavica Shumilo and Spasskaja, 1975 but differs from it in the larger number and size of the rostellar hooks, the larger size of the rostellar sac, the smaller size of the testes, and situation of the genital pores. Neyraia turdi n. sp. differs from all the known 7 species of the genus in absence of the neck, the cirrus pouch and cirrus armed with spines, and shape of the rostellar hooks.

Key words: avian cestodes; Sobolevitaenia turdi; Sobolevitaenia oitaensis; Neyraia turdi; Turdus sibiricus; morphology.