_Worker._ Length 1 line. Rufo-testaceous and very smooth and shining; the antennae as long as the insect; the flagellum, mandibles, tarsi, and articulations of the legs pale testaceous. The thorax narrowed anteriorly into a short neck, behind which it is dilated, the sides being rounded, the meso- and metathorax narrower and of nearly equal width, the spines of the metathorax minute and slender. The first node of the petiole somewhat wedge-shaped, the second globose, the abdomen very smooth and shining; club of the antennae 3-jointed. _Hab._ Aru. I can detect no specific difference between this and _Myrmica laevigata_, taken by myself in the neighbourhood of London; but it is not uncommonly met with in hothouses, near to which I captured my specimen. I believe _M. laevigata_ is identical with _OEcophthora pusilla_, the House-Ant of Madeira. 5. MYRMICA MELLEA. _M._ capite thoraceque flavis; abdomine pallide fusco. _Worker._ Length 1-3/4 line. Head, antennae, thorax, and legs honey-yellow and very smooth and shining; thorax strangulated at the base of the metathorax, which is not spined; the first node of the abdomen is oblique anteriorly, and vertical behind, the second node subglobose. Abdomen: the base honey-yellow, the apical margin of the first segment, and the following segments entirely, pale fuscous; the club of the antennae 2-jointed. _Hab._ Aru. 6. MYRMICA CARINATA. _M._ obscure fusco-ferruginea; thorace rufo-fulvo; capite thoraceque carinis irregularibus; metathorace spinis duabus longis armato. _Worker._ Length 1-1/4 lines. Head and abdomen black, with more or less of an obscure ferruginous tinge, particularly at the vertex and base of the abdomen; the thorax and nodes of the petiole ferruginous; the legs rufo-piceous, with the tarsi and articulations ferruginous, the antennae and mandibles ferruginous; the head and thorax with irregular distant longitudinal carinae; the sides of the thorax rugose; the spines on the metathorax long and acute; the abdomen very smooth and shining; the club of the antennae 3-jointed. _Hab._ Aru. Gen. CREMATOGASTER, _Lund_. 1. Crematogaster obscura, _Smith, Cat. Hym. Ins., Journ. Proc. Linn. Soc._ ii. 76. 4 [Symbol: Mercury]. _Hab._ Aru; Borneo. 2. CREMATOGASTER ELEGANS. _C._ pallide rufo-testaceus; abdomine nigerrimo nitido; thorace bispinoso. _Worker._ Length 3/4 line. Entirely pale rufo-testaceous, excepting the eyes and abdomen which are jet black; the nodes of the petiole pale, smooth, and shining. Head about the same width as the abdomen. The lateral angles of the anterior margin of the prothorax acute, the metathorax armed with two long acute spines. Abdomen heart-shaped, its apex acute. _Hab._ Aru. 3. CREMATOGASTER INSULARIS. _C._ niger, laevis et nitidus; antennis tarsisque pallide testaceis; thorace spinis duabus acutis armato.