The adult male of Xenos colombiensis n. sp. is described from a specimen extracted from the pupal case of its host, Polistes meyersi. While several species of Strepsiptera are known to parasitze species of Polistes in South America, this is the first species known to parasitize P. meyersi. An identification key is provided for adult males of Xenos species parasitizing Polistes species in the New World.