The Ants of the Genus Proceratium (Hymenoptera : Formicidae) in Japan(Systematics, Morphology and Evolution)

The ant genus Proceratium in Japan is taxonomically revised. All castes (worker, queen, and male) of the four species, P. itoi, P. japonicum, P. morisitai new species, and P. watasei are described or redescribed, keyed, and illustrated with ecological notes. The first descriptions for the queen of P. itoi and the males of P. japonicum and P. watasei are given. All the four species have olfactory sensilla basiconica distributed on a particular area of the apical antennal segment and appendages of peculiar form on the galea. Palp formulae are surveyed and discussed. Wing venation is studied and a key based on the wings only is given. Male genitalia and subgenital plates are examined and illustrated.