MOUNTAIN ANTS OF NORTH AMERICA. 493 



unreserv'edly agree with those who repudiate all such connections, 

 with the exception of the Siberian-Alaskan and possibly the North 

 Atlantic bridges. I am quite unable to find anything in the neo- 

 tropical ant-fauna that makes it necessary to assume former connec- 

 tions of South America with Australia or with Africa. The only 

 genus supposed to be peculiar to Australia and South America is 

 Melophorus, which is represented by numerous species in the former 

 region and to which Forel and Emery referred a few Chilian and Pata- 

 gonian species formerly regarded as belonging to the holarctic genus 

 Lasius. But Emery later showed that the Chilian and Patagonian 

 forms really constitute a distinct subgenus, which he called Lasio- 

 phancs. From a recent study of the Australian species I am convinced 

 that the}^ should be generically separated from the South American 

 species. So far as Africa and South America are concerned, they have 

 no genera in common which have not a much wider distribution in the 

 Palearctic or Oriental regions. 



Among the numerous writers on geographical distribution who have 

 recently rejected or ignored the speculations of the bridge-builders, 

 I will consider only Kolbe, Handlirsch and Matthew, as they seem to 

 me to have reached conclusions very similar to those suggested by my 

 study of the Formicidae. These writers recall those who, like Allen 

 (1878), Scribner (1882) and Haacke (1887) long ago pointed to the 

 north polar region as the original center of organic distribution, but 

 differ in placing this center in Central or Eastern Asia. Kolbe (1913) 

 calls attention to the vast extent and great permanence of the Asiatic 

 continent during geologic time as contrasted with Europe and selects 

 the region between the Caspian Sea and Eastern China, and especially 

 Turkestan and Thibet, as the most ancient of the sources and reser- 

 voirs of Palearctic animal life. This is indicated by both the mam- 

 mals and the insects. Of the single beetle genus Carabus Central Asia 

 alone possesses 35 endemic subgenera! Europe is merely a zoogeo- 

 graphical appendix of Asia, to which the African, Australian and North 

 American faunas are easily traceable by emigration during the Cre- 

 taceous when there existed a broad Siberian-Alaskan land-bridge. 



Kolbe does not discuss the origin of the neotropical fauna nor the 

 antarctic and other land-bridges, but Handlirsch (1913) comes to close 

 grips with these constructions in a valuable statistical study of more 

 than 16,000 insect genera, comprising 180,000 species or about one third 

 of the known forms. His results in regard to the distribution of the 

 endemic as contrasted with the more widely distributed genera in the 

 various geographical regions are given in the following interesting 

 table: 



