138 SMITH ON HTMENOPTEEA OF ARU ISLANDS. 



well as the mandibles obscurely ferruginous ; the apex of the flagellum 

 and the apical joints of the tarsi pale rufo-testaceous. Thorax rounded 

 anteriorly, compressed behind, with the metathorax abruptly truncate. 

 The scale of the petiole narroAV, incrassate, its anterior margin slightly 

 curved, its posterior margin straight ; the abdomen ovate. 



Worker minor. About 3 lines long, very like the larger worker, the 

 head being truncate in front ; but it is, in proportion to the thorax, 

 narrower ; the latter is compressed and abruptly truncate ; in other 

 respects it agrees with the worker major. 



Hab. Aru. 



10. Formica l^vissima. F. nigra nitida laevissima, sparse pilosa ; 

 squama oblonga subdepressa. 



Worker. Length 4 lines. Jet-black, very smooth and shining; head 

 wider than the thorax, slightly emarginate behind, the sides slightly 

 rounded; the anterior margin of the clypeus rounded, the mandibles 

 striated and obscurely ferruginous ; the scape with a few glittering 

 silvery-white hairs. Thorax not quite so wide as the head an- 

 teriorly, narrowed behind, with the disk somewhat flattened, slightly 

 convex, a deep strangulation between the meso- and metathorax, 

 the latter obliquely rounded ; the legs and abdomen sprinkled with 

 glittering white hairs. The node of the petiole incrassate, very slightly 

 elevated ; viewed sideways, broadly wedge-shaped ; the abdomen ovate. 



Hab. Aru. 



11. Formica nitida. F. capite abdomineque nigris, antennis tho- 

 raceque pedibusque rufo-testaceis laevissirnis et lucidis. 



Worker. Length 4 lines. Head and abdomen shining black; the 

 flagellum, thorax, legs, and scale of the petiole rufo-testaceous ; the 

 legs palest ; the scape fuscous, with its base pale ; the head large, 

 wider than the abdomen, and emarginate behind ; the clypeus and 

 mandibles obscurely ferruginous. Thorax compressed, not strangu- 

 lated in the middle. The scale of the petiole narrow, with its margin 

 rounded above ; abdomen ovate, and sprinkled with a few erect pale 

 hairs. 



Hab. Aru. 



12. Formica scrutator. F. nigerrima, mandibulis tarsorumque 

 articulo apicali pallide ferrugineis, thorace medio profunde coarctato. 



Worker. Length l|-2 lines. Shining black ; the mandibles pale, fer- 

 ruginous, with their inner margins finely denticulate ; the eyes placed 

 rather forwards on the sides of the head, the latter emarginate be- 

 hind. Thorax deeply strangulated in the middle; the metathorax 

 elevated and obliquely truncate behind. Abdomen ovate ; the scale 

 of the petiole sub-incrassate, with its margin rounded above; the 

 insect very thinly covered with a fine cinereous pile. 



Hab. Aru. 



