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 fr om natural grassland in Argentina. Other samples were collected from a fallow field previously cultivated with potatoes. Scanning electron m icrographs are presented for F. dittisimus, F. facultativus, F. balogh i, F. balcarceanus sp. n. and Coslenchus rhombus. Filenchus balcarcean us sp. n. is distinguished by its lateral field with two lines setting off a single band which bears 2-4 irregular lines seen only by SEM. t he variable head shape and annulation. The five species are first reco rds from Argentina.