The rare Neotropical ant subfamily Leptanilloidinae is revised and its internal phylogeny and biogeography discussed. A new genus, Asphinctanilloides gen.n., including three new species, A. amazona, A. anae and A. manauara, and three new species of Leptanilloides, L. improvisa, L. legionaria and L. sculpturata are described. The only previously known species of the subfamily, L. biconstrictaMann ... [Show full abstract] (1923), is redescribed, and the larva of L. legionaria sp.n. is described. Keys to the genera and the species, and a phylogeny of the group are provided. Emphasis has been placed on the study of abdominal and sting characters.