A Supplement to the Revisions of the Dacetine Ant Genera Orectognathus and Arnoldidris, With Keys to the Species

The Orectognathiti are a small group of dacetine ants found in the Australopapuan area, grouped into two genera, Orectognathus Fr. Smith and Arnoldidris Brown. Previous revisions (Brown, 1950, 1953) have recognized nine species in the first and four in the latter genus; of these, I had been able to study directly only six species of Orectognathus from satisfactory material and under favo.rable conditions. Recently, however, I have been able to see additional material collected by E. 0. Wilson in New Caledonia and New Guinea, and in eastern Australia by Father C. Mercovich and myself. Furthermore, through the kind help of Curator Elisabetha Bajri of the Hungarian National Museum, I ha.ve been loaned the types of Orectognathus csikii SzabS, Arnoldidris biroi (SzabS), A. horvathi (SzabS) and A. chyzeri (Emery). During a hurried visit o the British Museum, I saw the type o.f Arnoldidris longispinosus (Donisthorpe), but was unable to make a proper sketch or notes beyond the affirmation of the species as a true Arnoldidris .of the biroi group. In the present paper, I propose to add two new orectognathite species and to offer notes on the characters, biology and distribution of some older ones. F.or the sak.e of a complete treatment and full keys, i have included notes and a figure of the manuscript species as derived from the characterization of (O. nigriventris) by Father Mercovich. It may be some time before the formal .description of Father Mercovich’s species appears in print, and neither he nor I intend that the preliminary inf.orma-