How Animals Work. 



" is more or less compact. That employed by ants of 

 a certain size, such as the black and mining ants, appears 

 to be less carefully chosen and forms a paste less fine 

 than that of which the brown, microscopic, and yellow 

 ants form their abode. It is, however, adapted to their 

 capacities, to their needs, and to the nature of the edifice 

 they intend to build. Thus the hillock raised by the 

 black ants always has thick walls formed of coarse, 

 lumpy earth, well-marked stories, and large chambers 

 with vaulted ceilings resting upon solid pillars ; we 

 never find roads or galleries properly so called, but 

 large cavities and extensive embankments of earth. We 

 further notice that the little architects have preserved 

 a certain proportion between the widely arched ceilings 

 and the pillars which are to support them." 



Of the little brown ant, whose body only measures 

 one-eighth of an inch in length, Hiiber gives the follow- 

 ing interesting description : " This ant, one of the most 

 industrious of its tribe, forms its nest in stories rather 

 less than half an inch in height. The partitions are not 

 more than one-twenty-fifth of an inch in thickness, and 

 the substance of which they are composed is so finely 

 grained that the surface of the inner walls appears quite 

 smooth and unbroken. These stories are not hori- 

 zontal ; they follow the slope of the ant-hill, so that 

 each curves over all those which lie below it, down to 

 the ground floor, which communicates with the sub- 

 terranean lodges. They are not always, however, ar- 

 ranged with the same regularity, for ants do not follow 

 an invariable plan; it appears, on the contrary, that 

 nature has allowed them a certain amount of freedom 

 in this matter, and that they can vary their method 



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