[2 new filariae of a monkey, Saimiri sciureus, in Guyana]

Description of two new Filariae, parasites of Saimiri sciureus L. (Georgetown type, karyotype 14/7) from Guyana. Dipetalonema robini n. sp., fourth species of the genus, is frequent and associated with the morphologically similar species, D. gracile (Rud., 1809); D. robini differs from D. gracile by structure of caudal lappets of female, vagina, microfilaria and area rugosa. The second filaria, also frequent, belongs to the subgenus Tetrapetalonema which contains a dozen species; Mansonella (T.) mariae n. sp. is similar to M. (T.) marmosetae Faust, 1935 and M. (T.) tamarinae Dunn & Lambrecht, 1963 but is distinguished by the position of the head papillae, the cuticular ornamentation of the body and the microfilaria.