Acrotaphus Townes, 1960 is a moderately large New World genus of spider attacking parasitoid wasps. Previously, it comprised 11 species. The present study aims to review the genus, and includes descriptions of 15 new species: A. amajari sp. n., A. amazonicus sp. n., A. bodoquenaensis sp. n., A. cuzconus sp. n., A. dolichopus sp. n., A. homeofranklini sp. n., A. jackiechani sp. n., A. kourou sp. n., A. micrus sp. n., A. monotaenius sp. n., A. nambilloensis sp. n., A. pseudoamazonicus sp. n., A. pseudomexicanus sp. n., A. venezuelanus sp. n. and A. zampieronae sp. n.. In addition, we present new characters for the study of the genus and describe the male genitalia for the first time. An illustrated key and maps to the species of the genus are provided. Acrotaphus franklini Gauld, 1991 and A. pseudoamazonicus sp. n. were recorded from the nests of Trypoxylon (Trypargilum) lactitarse Saussure, 1867 (Hymenoptera: Crabronidae).
Keywords: Hymenoptera, Amazonia, biodiversity, koinobiont, Neotropical, parasitoids, Polysphincta genus group, rain forest, spiders, South America, taxonomy.