140 SMITH ON HYMENOPTERA OF ARU ISLANDS. 



5. PoLYRHACHis LONGIPES. P. nigcr ; flagelli dimidio apicali ti- 

 biisque anticis pallide ferrugineis, prothorace petiolique squamula 

 bidentatis. 



Worker. Length 3 lines. Black ; the head and thorax finely rugose ; 

 the antennae elongate, longer than the insect ; the apical half of the 

 flagellum pale ferruginous. Thorax rounded above, the sides not 

 margined ; two spines on the thorax anteriorly, two on the meta- 

 thorax, and two on the scale of the petiole ; the legs elongate, with 

 the anterior tibiae ferruginous. Abdomen globose, sometimes rufo- 

 fuscous, or the base obscurely rufous. 



Hab. Aru. 



6. PoLYRHACHis SERRATUS. P. uiger ; capite thoraceque rugosis, 

 abdomine dense punctato, squama petioli transversa, margine supemo 

 serrata. 



Worker. Length 2 lines. Black, with the antennae and legs ferru- 

 ginous. Thorax oblong-quadrate or very slightly narrowed towards 

 the metathorax, slightly convex above, not margined at the sides, the 

 divisions not perceptible ; the head and thorax rugose and pubescent. 

 Abdomen globose, shining, and closely punctured ; the scale of the 

 petiole transverse above, produced into an acute spine on each side, 

 the upper margin finely serrated, the lateral margins narrowed to their 

 base, and having two or three small sharp spines. 



Hab. Aru. 



7. PoLYRHACHis scuTULATUs. P. uigcr, fortitcr politus et lucidus, 

 metathorace petiolique squamula dente longo curvato acuto in latere 

 utroque, pedibus nigro-ferrugineis. 



Worker. Length 2| lines. Black and very smooth and shining ; the 

 legs dark ferruginous. Thorax : the disk expanded, slightly convex 

 above, with the margins acute and curving upwards ; the anterior 

 margin transverse, rather wider than the head, with the lateral angles 

 slightly curved forwards, and very acute ; the lateral margins of the 

 prothorax curved backwards and inwards ; the margins of the meso- 

 thorax are rounded ; the pro- and mesothorax highly polished above, 

 forming an escutcheon-shaped disk; the metathorax opake, and 

 sprinkled with a few short glittering hairs, armed posteriorly with 

 two long very acute spines, divergent and directed backwards. Ab- 

 domen globose ; the scale of the petiole with two long curved acute 

 spines, directed backwards to the curve of the abdomen. 



Hab. Aru. 



8. PoLYRHACHis MUCRONATUS. P. laevis, uitidus, niger; thorace 

 spinis duabus crassis compressis acutis postice armato. 



Worker. Length 2\ lines. Black, smooth, and shining, very deli- 

 cately and indistinctly aciculate ; the antennae beneath and the tibiae 

 and femora obscurely ferruginous, the anterior and intermediate tibiae 

 brightest ; the apex of the mandibles ferruginous. Thorax transverse 



