ANT-NESTS. 



'93 



save labor. The irregular form of the cavities is a characteristic so uni- 

 versal in ant-nests that it would seem to be preferred to a monotonous 

 regularity. It may be important, in fact, in enabling the ants to orient 

 themselves readily. The nest entrance is sometimes peculiarly modi- 

 fied to suit the needs of the various species. It may be left permanently 





V ; '. 



'^*y,; .' 



*&4^u 



FIG. 106. Superficial galleries of Acanthomyops latipes as they appear on removing 

 the stone that covers them. About ;4 natural size. (Original.) 



open and guarded by workers or soldiers, or it may be closed at night : 

 it may be enlarged or constricted for the purpose of regulating the 

 ventilation of the cavities and preventing the inroads of enemies, it 

 may be adroitly concealed or exposed to view and surrounded by con- 

 spicuous earth-works. 



Even in this prevailing and opportunistic irregularity, however, 

 there are singular differences of degree. The more primitive ants, 

 like the Ponerinas, build with a certain irregularity devoid of character. 

 The Dorylinse may hardly be said to build nests at all, but merely to 

 bivouac in some convenient cavity under a stone or log. or they may 

 temporarily occupy the nests of other ants or dig irregular runways 

 beneath the surface of the soil. The higher ants, however, which form 



