The vast majority of Cretaceous ants belong to stem-group Formicidae and comprise workers and reproductives of largely generalized morphologies... recent discoveries from the Cretaceous suggest relatively advanced social levels. Remarkable exceptions to this pattern of generalized morphologies are ants with bizarre mouthparts in which both female castes have modified heads and bladelike mandibles that uniquely move in a horizontal rather than vertical plane... with the mandibles apparently acting as traps triggered by sensory hairs in a way distinct from that of modern trap-jaw ants... some of the most effective predatory ants are solitary hunters with powerful trap jaws... Dr. WANG...