Tylenchidae from Buenos Aires, Argentina.

Five species belonging to the genus Filenchus, including a new species and one species of Coslenchus were found in soil samples collected from natural grassland in Argentina. Other samples were collected from a fallow field previously cultivated with potatoes. Scanning electron micrographs are presented for F. dittisimus, F. facultativus, F. baloghi, F. balcarceanus sp. n. and Coslenchus rhombus. Filenchus balcarceanus sp. n. is distinguished by its lateral field with two lincs setting off a single band which bears 2-4 irregular lines seen only by SEM, the variable head shape and annulation. The five species are first records from Argentina.