Mason-Ants. 281 



and long held it frozen ; the ants were in many cases not 

 more than four inches beneath the surface, and must have 

 been enclosed in a mass of frozen soil for a long period ; yet 

 they, their young, and the onisci, were perfectly uninjured 

 by it : affording another proof of the fallacy of the commonly 

 received opinion, that cold is universally destructive to insect 

 life."* 



The earth employed by m'ason-ants is usually moist clay, 

 either dug from the interior parts of their city or moistened 

 by rain. The mining-ants and the ash-coloured (Formica 

 fusca) employ earth which is probably not selected with so 

 much care, for it forms a much coarser mortar than what we 

 see used in the structure of the yellow ants (F. flava) and 

 the brown ants (jP. brunnea). We have never observed them 

 bringing their building materials of this kind from a distance, 

 like the mason-bees and like the wood or hill ant (F. rufa) ; 

 but they take care, before they fix upon a locality, that it 

 shall produce them all that they require. We are indebted 

 to Huber the younger for the most complete account which 

 has hitherto been given of these operations, of which details 

 we shall make free use. 



" To form," says this shrewd observer, " a correct judgment 

 of the interior arrangement or distribution of an ant-hill, it 

 is necessary to select such as have not been accidentally 

 spoiled, or whose form has not been too much altered by 

 local circumstances ; a slight attention will then suffice to 

 show that the habitations of the different species are not all 

 constructed after the same system. Thus, the hillock raised 

 by the ash-coloured ants will always present thick walls, 

 fabricated with coarse earth, well-marked stories, and large 

 chambers, with vaulted ceilings, resting upon a solid base. 

 We never observe roads, or galleries, properly so called, but 

 large passages, of an oval form, and all around considerable 

 cavities and extensive embankments of earth. We further 

 notice, that the little architects observe a certain proportion 

 between the large arched ceilings and the pillars that are to 

 support them. 



* Journal of a Naturalist, p. 304. 



