COLLECTED AT BACHIAN, KAISAA, ETC. 97 



cous, the flagelluni pale rufo-testaceous ; the tips of the mandibles 

 ferruginous, their innei- margin with three or four short acute teeth, 

 their apex forming a long stout acute tooth. Thorax elongate, nar- 

 rowest behind and slightly compressed ; the legs elongate, slender, 

 ferruginous and slightly pubescent. Abdomen ovate, the apical mar- 

 gins of the segments rufo-piceous ; the node of the peduncle wedge- 

 shaped and pointed above. 

 Hab. Dory. 



This species resembles the worker of F. gigas, which is found in India, 

 Malacca, Singapor, Borneo, &c., but the head is different in form, the 

 colour is different, and the form of the scale of the peduncle differs too 

 much, I think, for the insect to be considered as a form of F. gigas ; it must, 

 however, be one of the largest known species of the FormicidcB. 



12. Formica DESECTA. F. nigra nitida; capite antice truncate. 



Female. Length 4^ lines. Jet black, shining ; the head wider than the 

 thorax, truncate anteriorly; the truncation and sides of the head rugose ; 

 the mandibles rugose ; the ocelli placed wide apart in a triangle, the 

 posterior pair situated on the hinder margin of the vertex ; the eyes 

 ovate, placed very high on the sides of the head; the antennae reach- 

 ing to the insertion of the wings, the flagellum rufo-testaceous. Tho- 

 rax, oblong-ovate, very smooth and shining; the wings hyaline and 

 iridescent, the nervures pale rufo-testaceous. Abdomen oblong-ovate ; 

 the node of the peduncle incrassate, truncate above. 



Hab. Dory. 



Gen. Tapinoma, Foerst. 



\. Tapinoma pratensis. T. capite, thorace, pedibusque pallide fer- 



rugineis ; abdomine fusco-nigro. 

 Worker. Length \\ line. Head and thorax pale ferruginous, smooth 



and shining ; the antennae and legs pale testaceous. Abdomen dark 



fuscous and sub-opake ; the scale of the peduncle ovate, hidden 



beneath the base of the abdomen. 

 Hab. Bachian. 



Gen. PoLTRHACHis, Smith. 



\. Polyrhachis bihamatus, Drury, Ins. ii. pi. 38. f. 8. $ . 



Hab. India ; Borneo ; Sumatra ; Bachian. 



The curved spines or hooks with which this remarkable species is armed 

 vary greatly in different individuals, not only in being more or less 

 curved or elongate, but the two spines which rise from the peduncle 

 of the abdomen, on a short base, are sometimes widely divergent ; in 

 other individuals, they are continued nearly parallel, only curving 

 apart, outwardly, at their summit ; in the specimens from Bachian 

 the spines are shorter and stouter than in any I have previously ex- 

 amined, — but I can only regard this as a local variety of the Indian 

 species. 



