HYMENOPTERA. 25 



emarginate. Thorax usually more or less fuscous in front, com- 

 pressed behind. Abdomen shining, the apical margins of the 

 segments narrowly testaceous ; the scale of the peduncle ovate 

 and ferruginous. 



Hab. Borneo (Sarawak). (Coll. W. W. Saunders, Esq.) 



85. FOKMICA IRRITABILIS. B.M. 



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

 abdomen, ferruginous, the legs rufo-fuscous ; i-bdomen nearly 

 black ; the scajjc black, with the extreme base and apex as well 

 as the flagellum ferruginous, the latter more or less fuscous 

 above ; the vertex has sometimes a fuscous stain ; the mandibles 

 nigro-piceous, their apex ferruginous. Thorax com])ressed 

 behind, much narrower than the head, both thinly sprinkled with 

 erect reddish hairs; the legs nigro-fuscous, with the base and 

 apex of the joints, and sometimes with the coxse and a])ical joints 

 of the tarsi, ferruginous. Abdomen : the scale oblong- ovate, 

 pointed above; the apical margins of the segments with a thin 

 fringe of reddish-yellow hairs. 



Hab. Borneo (Sarawak). 



86. Formica srdula. 



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

 the mandibles and legs shining black ; the abdomen chestnut- 

 red. The mandibles with five stout teeth, and with their apex 

 striated ; the head much wider than the thorax, deeply emar- 

 ginate behind ; the flagellum obscurely ferruginous. Thorax 

 compressed behind ; the trochanters and apical joints of the 

 tarsi ferruginous. Abdomen ovate; the scale of the peduncle 

 subquadrate, slightly emargiuate above ; the abdomen thinly 

 sprinkled with reddish pubescence, and a few scattered black 

 hairs on the head and thorax. 



Hah. Borneo (Sarawak). (Coll. AV. W. Saunders, Esq.) 



87. Formica exasperata. 



Worker. Length 5.V lines. — Head, thorax, and scale of the 

 peduncle, blood-red, the abdomen black ; a dark stain in front 

 of the anterior stemma, and usually a second at the insertion of 

 the antenutic ; these stains sometimes obsolete ; the mandibles 

 black, stout, ])unctured and strongly toothed ; the head much 

 wider than the thorax and deeply •:'marginate behind. Thorax 

 compressed behind, usually more or less stained at the sides ; 

 the tibia3 and tarsi more or less fuscous. Abdomen with the 



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