58 me. smith's catalogue of hymenopterous insects 



dark, but all have the scale of the same elongate-ovate form, without 

 any notch above. 



20. Formica irritans. F. nigra; antennis, thorace pedunculisque 

 squama ferrugineis. 



Worker. Length 6 lines. Head and abdomen nigro-fuscous ; antennae, 

 thorax, and scale of the abdomen, as well as the legs, ferruginous. 

 Elongate and slender, the head ovate ; the apex of the scape ferru- 

 ginous; the clypeus and mandibles dark rufo-piceous. The thorax 

 elongate, compressed, with the prothorax slightly dilated at the sides. 

 Abdomen ovate : the scale incrassate, rounded anteriorly, and truncate 

 behind ; the entire insect thinly sprinkled with erect, long, pale pu- 

 bescence. 



Worker (minor). Length 3 lines. This only differs in having the antennae 

 entirely pale ferruginous. 



Hab. Borneo (Sarawak). 



This is probably the worker of Formica diligens. 



Genus Tapinoma, Foerster. 



1. Tapinoma glabrata. T. nigra, subnitida, glabra, angustior; 

 antennis, mandibulis tarsisque rufo-pallidis ; squama oblonga de- 

 pressa; abdomine oblongo-ovato. 



Worker. Length 1§ line. Black: the clypeus obscurely testaceous; 

 the mandibles and flagellum rufo-testaceous, the apex of the latter 

 slightly fuscous ; the head, prothorax, and coxae beneath, rufo-testa- 

 ceous ; the thorax declining above to the base of the metathorax, the 

 latter convex ; the tarsi pale rufo-testaceous. Abdomen ovate ; the 

 scale inclining forwards in a hne with the oblique truncation of the 

 metathorax ; the insect entirely destitute of pubescence. 



Hab. Malacca. 



Genus Polyrhachis. 



Body more or less armed with spines. Antennce elongate, usually 

 nearly as long as the body ; labial palpi 4-jointed, the basal joint 

 shortest, the three following, each in succession, longer than the pre- 

 ceding ; the apical joint three times the length of the basal one. 

 Maxillary palpi 6-jointed, elongate, the basal joint short, about half 

 the length of the second joint, each of the following joints more than 

 twice the length of the second joint. Thorax : subovate in the 

 females ; compressed and frequently flattened above in the workers ; 

 wings as in Formica ligniperda. Abdomen globose. (Details, Plate I,) 



This genus of Ants, of which the Formica bihamata may be 

 regarded as the type, forms a very distinct section of the Formi- 

 cidce : the males I am not acquainted with. The habit of these 

 insects is arboreal, as we learn from Mr. Jerdon, who, in his 

 paper on Ants, in the Madras Journal, describes two species ; of 



