PARATYLENCHINAE - MORPHOLOGY OF SOME KNOWN SPECIES AND DESCRIPTIONS OF GRACILACUS-BILINEATA SP-N AND GRACILACUS-VERA SP-N (NEMATODA, TYLENCHULIDAE)

Ten species of Paratylenchus and six of Gracilacus are discussed. P. i taliensis, P. tateae and P. labiosus are synonymized with P. similis. Measurements of specimens from various populations are presented, and previously published morphometric data compiled in tables to character ise known limits of species variation. The significance of morphology of males and juveniles in identification of these nematodes is shown i n descriptions of various species. It is demonstrated that in G. macro dora the third stage juvenile lacks a stylet, while the fourth stage j uvenile has a well developed stylet and oesophagus and apparently feed s. G. bilineata sp. n. from Taiwan has only two incisures, lips not pr otruding, stylet 46 (43-50) mu m, V = 73-78, no vulval flaps, and male s with very thin stylet. G. vera sp. n. from Mexico is characterized b y having sublateral lips projected anteriorly, four incisures, stylet 78 (66-86) mu m, V = 76-79, small vulval flaps, and males without styl ets.