CHAPTER IX. 



THE GEOGRAPHICAL DISTRIBUTION OF ANTS. 



" These craggy regions, these chaotic wilds, 

 Does that benignity pervade, that warms 

 The mole contented with her darksome walk 

 In the cold ground; and to the emmet gives 

 Her foresight, and intelligence that makes 

 The tiny creatures strong by social league; 

 Supports the generations, multiplies 

 Their tribes, till we behold a spacious plain 

 Or grassy bottom, all, with little hills 

 Their labour, covered, as a lake with waves ; 

 Thousands of cities, in the desert place 

 Built up of life, and food, and means of life ! " 



Wordsworth, " The Excursion," Book IV. 



Few circumscribed groups of animals have a more significant geo- 

 graphical distribution than the ants. As colonies they are fettered to 

 the soil or vegetation, but their winged females, though feeble flyers, 

 may be wafted long distances by the wind and thus overcome mountain 

 and water barriers of considerable magnitude. In these respects ants 

 resemble plants, which, though rooted in the ground, are able never- 

 theless greatly to extend the range of their species by means of wind- 

 or animal-borne seeds. That ants are often carried by air currents to 

 great distances beyond their normal range is attested by a number of 

 facts. Annually numbers of female ants are wafted out to sea or into 

 our great lakes to be drowned and eaten by fishes, or conveyed to deso- 

 late mountain summits where they perish in futile attempts to found 

 colonies. Occasionally however such widely dispersed females do suc- 

 ceed in establishing themselves and in rearing their offspring. Accord- 

 ing to Forel (icpirn) the Occident ant (Pogonomyrme.r occidentalis), 

 a species peculiar to the Great Plains, has been taken in Hawaii, 

 and King (19010) has found in Massachusetts a single colony of 

 Formica ncoclara, an ant restricted, so far as known, to the mountain 

 valleys of Colorado. 



This method of dispersal is, of course, denied to all ants like the 

 Dorylinse, certain Ponerinse and Myrmicinae, whose females are wing- 

 less, since these insects cannot cross bodies of water nor high moun- 

 tain ranges. But as the Dorylinse are migratory ants, and, as a rule, 

 do not inhabit permanent nests, their colonies compensate, to a certain 



