Description of D. freitasi n. sp., a parasite of Cebus capucinus: this species, close to D. caudispina, is distinguished by the slightly more complex structure of the vagina and right spicule, the lack of area rugosa on the tail and by the shorter microfilaria. Additional morphological data on the male of D. robini Petit et al., 1985 are given. A comparative table of 4 principal evolutive characters of the genus Dipetalonema (vagina, left and right spicules, epithelio-muscular body wall) is given. D. caudispina and D. freitasi n. sp. represent a small primitive group opposed to the more evolved one made up of D. robini, D. gracile and D. graciliformis.