NEW TYLENCHS (NEMATODA) FROM KOREA

Merlinius acuminatus Minagawa of medium length has a short stylet (12-14-mu-m), a double spermatheca and a long conical tail; in the male the bursa does not cover the entire tail. It is close to M. joctus, which has a longer stylet (15-17-mu-m). Two new Triversus species permitted a further study of the genus: apparently the dorsoventral flattening of the head, the presence of intestinal fasciculi, the structure of female and male reproductive systems and the shortness of the male tail vs the long, conical female tail are genus characteristics as well. T. kangwonensis sp. n. and T. yugaensis sp. n. resemble T. annulatus but have a gently annulated cuticle (instead of coarsely), moreover in T. kangwonensis the tail is longer with numerous annuli (c' = 4.4-6.1 instead of c' = 2.7-3.5); T. yugaensis sp. n. is larger (L = 780-935-mu-m instead of L = 620-760-mu-m) and has a shorter stylet (17-19-mu-m instead of 19-22-mu-m). Pratylenchoides clavicauda sp. n. has six lines in the lateral field, a non-annulated tail end and a long overlapping oesophageal lobe. Structure of tail and oesophageal lobe is used to differentiate it from the closely related P. leiocauda, P. utahensis and P. alkani.