56 MR. SMTTIl's CATALOGUE OF HYMENOPTEEOUS INSECTS 



legs very much elongated, the posterior pair one-third longer than the 

 insect, the tibiae and tarsi pale testaceous ; the abdominal scale incras- 

 sate, rounded in front and truncate behind ; the abdomen dark rufo- 

 piceous, short and ovate ; the base more or less pale ferruginous. 

 Hab. Singapore. 



14. Formica irritabilis. F. capite, thorace et squama sanguineis ; 

 pedibusque rufo-fuscis ; abdomine fusco-nigra. 



Worker. Length 4 lines. Head, thorax, and scale of the abdomen 

 ferruginous, the abdomen black ; the scape black, its extreme base 

 and apex, and the flagellum, ferruginous, the latter more or less 

 fuscous above ; the vertex with sometimes a fuscous stain ; the man- 

 dibles nigro-piceous, then apex ferruginous ; the thorax compressed 

 behind, and thinly covered, as well as the head, with erect reddish 

 hairs ; legs nigro-fuscous, with the base and apex of the joints, or 

 with sometimes the coxae and base of the femora, and also the apical 

 joints of the tarsi, ferruginous. The scale of the abdomen ovate, 

 terminating in a point above ; the apical margins of the segments 

 with a thin fringe of pale reddish -yellow hairs. 



Hab. Borneo (Sarawak). 



15. Formica sedula. F. capite thorace pedibusque opacis nigris, 

 abdomine castaneo. 



Worker. Length 5 lines. Head and thorax opake-black, the man- 

 dibles and legs shining black ; the abdomen chestnut-red. The man- 

 dibles smooth at their base, and striated at their apex, with five stout 

 teeth, the flagellum fusco-ferruginous ; the head deeply emarginate 

 behind ; much wider than the thorax ; the thorax compressed ; the 

 trochanters and apical joints of the tarsi ferruginous. Abdomen ovate 

 and thinly sprinkled with reddish pubescence ; the scale subquadrate ; 

 emarginate above, and slightly ferruginous ; the head and thorax with 

 a few erect black hairs. 



Hab. Borneo (Sarawak). 



Resembles F. compressa, but differs in having much stouter legs, in 

 being pubescent, in having the posterior angles of the head more 

 rounded, and in being pubescent. 



16. Formica exasperata. F. capite thorace abdominisque squama 

 sanguineis ; tarsorum unguibus abdominisque basi rufis ; thorace com- 

 presso. 



Worker. Length 5% lines. Head and thorax blood-red ; sometimes 

 blackish before the insertion of the antenna;, and also a little in front 

 of the anterior stemma ; in some examples entirely red ; the mandibles 

 black, stout, strongly toothed and punctured ; the head deeply emar- 

 ginate posteriorly, and much wider than the thorax. Thorax : com- 

 pressed, sometimes with fuscous stains at the sides, with the tibiae and 

 tarsi more or less fuscous; the head, thorax and legs with a thin 

 scattered pale reddish pubescence. Abdomen : black, subopake, 



