Three species of myrrnlclne ants, lachnomyrmex grandis, L. longinodus, and megalomyrmex bidentatus are described from tropical forests of southwestern Colombia. lachnomyrmex grandis is distinguished for its large size and coarser sculpture; L. longinodus by its long petiole and propodeal spines. Megalomyrmex bidentatus has two small but visible propodeal teeth, an exclusive character. among the known species of the genus. A key to the known neotropical Lachnomyrmex is provided.
