Abstract: The mandibles of Tatuidris tatusia workers are completely filled with glandular cells that represent a novel kind of intramandibular gland that has not been found in ants so far. Whereas the known intramandibular glands in ants are either epithelial glands of class-1, or scattered class-3 cells that open through equally scattered pores on the mandibular surface, the ducts of the numerous class-3 secretory cells of Tatuidris all converge to open through a conspicuous sieve plate at the proximal ventral side near the inner margin of each mandible.