The ants collected by the American Museum Congo Expedition. Wheeler, W. M. Bulletin of the American Museum of Natural History 1922 45 39 269 3JD9 urn:lsid:biosci.ohio-state.edu:osuc_concepts:2426 Insecta Formicidae Cataulacus Animalia Cataulacus Smith Hymenoptera 196 Arthropoda genus  Worker. - Small or medium-sized, rather flat, opaque or subopaque, black ants, with coarse sculpture and the head and thorax often dentate or spinulate on the sides. Antennae in all three phases 11-jointed with 3-jointed club and apically flattened or dilated scape. Head on each side with a deep scrohe situated beneath and external to the eye and capable of accommodating the whole of the folded antenna. The frontal carinae are far apart, anil diverge, but border the scrobes only at the base. The clypeus Ls wedged in between the frontal carinae and is not sharply delimited posteriorly. Thoracic sutures often indistinct or obsolete. Epinotum armed with spines. Petiole and postpetiole stout, the former usually more or less cuboidal, with a laminate process below, the latter subglobular. Gaster elliptical or suboblong, flattened, the first segment forming its whole dorsal surface. Legs rather short, the femora and tibiae incrassated. The female, though larger, closely resembles the worker. The pronotum is large and forms a considerable portion of the thoracic dorsum. Wings without a discoidal cell, with a single cubital and a narrowly open radial cell. The male resembles the female and worker in the shape of the head but has larger and longer petiole and postpetiole. The mesonotum has well-developed Mayrian furrows.  The ants of the genus Cataulacusbear a strange superficial resemblance, both in structure and habits, to those of the Neotropical genus Cryptocerus. The genus ranges over tropical Africa and eastward over Madagascar, India, Indonesia, and the Philippines, but is represented by the greatest number of species in the Ethiopian Region (Map 30). Concerning the habits, Arnold says that "all the species of this genus are tree-ants, usually forming medium-sized nests in hollow twigs and stems, or more rarely under the" bark. They are timid and slowmoving insects, often feigning death or dropping rapidly to the ground when disturbed." He has seen them breaking open the earthen tunnels constructed by termites on the trunks of trees and attacking the inmates.