276 bulletin: museum of comparative zoology. 



Of the forty-three genera recorded in the present paper, none are 

 pecuHar (Wheeleripone occurs also in Fiji). Typical Australian gen- 

 era are represented only by Rhytidoponera, Podomyrma, Turneria, 

 and Opisthopsis, each with a single species. 



The remaining genera are all widely distributed in Indo-Malaya. 

 Of these the following terminate their eastward distri})ution in the 

 Solomons : — Myopopone, Platythyrea, Cryptopone, Ectomomyrmex, 

 Crematogaster, Myrmecina, and Acropyga. 



Other genera, as Euponera, Anochetus, Vollenhovia, Tetramorium, 

 Pristomyrmex, Triglyphothrix, Oligomyrmex, and Polyrhachis are well 

 developed in the Papuan region, but extend eastward of the Solo- 

 mons in onl}' a few species, which are usually widely distributed. 



Two species of wide distribution, Lcptocjcnys dimhniia and Occo- 

 ■phyUa smaragdina, terminate their natural distribution in the Solo- 

 mons, for though the latter species occurs in Samoa, it is of recent 

 introduction. 



In general the Solomon Island ant fauna is Papuan, without pecu- 

 liar forms, and lacking a number of typical Papuan genera. The 

 Santa Cruz ant fauna is similar to that of the Solomons proper and 

 may be considered as the eastern limit of the Papuan subregion. 



The nearby island of Vanikoro has not been explored entomologically 

 but forests of Araucarians are known to occur there. This is then the 

 most northwestern locality for the Araucarinae and the island con- 

 taining it probably belongs to the Melanesian subregion, so a line 

 between the two islands separates the two subregions.^ 



In the preparation of this paper, I have been greatly assisted by 

 Prof. W. M. Wheeler of Harvard University, who has generously 

 permitted me to use his collection for comparison and has aided me in 

 certain determinations and in other ways. Prof. Carlo Emery, of 

 Bologna has kindly compared a number of species with types in his 

 collection. 



Most of the figures of new species were made by Dr. R. McEwen. 



1 The Melanesian subregion, (including Vanikoro, the New Hebrides, New Caledonia and 

 Fiji), like the Chilean and the Malagasy, might be described as a biological conservatory, where 

 types once tropicopolitan have been isolated and preserved, free from invasion. It is distinct 

 from Pajmasla though the presence of numbers of these relicts, and in negative characters, 

 lacking the majority of the plant and animal groups characteristic of the latter subregion. The 

 absence of any group which had its origin in this region is an important negative character. 



