2. ODONTOMACHUS TYRANNICUS. _O._ capite thoraceque nigris, antennis abdomineque ferrugineis, margine interno mandibulorum serratulo. _Worker._ Length 7 lines. Head oblong, narrowed behind, posteriorly deeply emarginate; the mandibles rufo-piceous, brightest at their apex, which is armed with two long teeth which are bent abruptly inwards, their tips black; the anterior portion of the head striated obliquely from the centre; the head, behind the anterior sulcation, very smooth and shining and having a deep longitudinal central depression. Thorax transversely striated, the articulations of the legs and the tarsi ferruginous. Abdomen smooth, shining, and ferruginous; the node of the petiole incrassate, cylindric, and tapering upwards into a very acute spine. _Hab._ Aru. 3. ODONTOMACHUS MALIGNUS. _O._ ferrugineus; capite supra oblique striato; margine interno mandibulorum confertim serrato; metathorace transversim striato; squama unispinosa; abdomine laevissimo. _Worker._ Length 7 lines. Ferruginous; the flagellum and legs palest; head much narrowed behind, the posterior margin deeply emarginate; mandibles smooth and shining, their inner margin strongly serrated, their apex abruptly bent or elbowed, and armed with two stout teeth; the face anteriorly evenly striated obliquely; the head behind the anterior sulcation very delicately striated obliquely. The prothorax smooth and shining, the meso- and metathorax transversely striated. Abdomen very smooth and shining; the node of the petiole incrassate and tapering upwards into an acute spine. _Hab._ Aru. This species most closely resembles _O. maxillaris_ from Brazil; but its smooth polished prothorax alone would distinguish it; its head is much broader anteriorly, and less elongate. Gen. PSEUDOMYRMA, _Guer._ 1. PSEUDOMYRMA LAEVICEPS. _P._ nigra, laevis et nitida; antennis, mandibulis, tibiis anterioribus, tarsisque rufo-fulvis. _Worker._ Length 2-1/4 lines. Black and shining; head very smooth and slightly emarginate behind, the eyes large and ovate; the mandibles and antennae rufo-fulvous. Thorax with the sides flattened, the disk slightly convex; a deep strangulation between the meso- and metathorax, the latter rounded above and oblique behind; the trochanters, articulations of the legs, and the tarsi rufo-fulvous. Abdomen thinly covered with a fine cinereous pile; the first node of the petiole somewhat oblong-ovate, the second subglobose, the petiole of the first node short. _Hab._ Aru. Gen. PODOMYRMA, _Smith_.