Lateral view of the metasoma of an A Ancistrocerus sur sp. n. male, with sternum II strongly truncate posterior to transverse furrow B A. cingulatus (Cresson) female, with sternum II convex posterior to transverse furrow C A. santaanna (de Saussure) male, with sternum II flat posterior to transverse furrow D Ventrolateral view of A. tuberculocephalus (de Saussure) female; sternum II with deep, longitudinal basomedian furrow. Frontal view of the clypeus for E A. arista (de Saussure) male with clypeus having a deep, semicircular emargination; and F A. lineativentris Cameron male with clypeus not having a deep, semicircular emargination. Dorsolateral view of vertex and pronotum of G A. tuberculocephalus (de Saussure) female, with pronotal carina present dorsolaterally and a polished tubercle posterior to ocelli; and H A. lineativentris Cameron male, with pronotal carina absent and vertex without tubercle. lbf = longitudinal basomedian furrow; tb = tubercle; dpc = dorsal pronotal carina.