176 



INSECT ARCHITECTURE. 



tiihe fitted exactly to its body {fig. c.) : it is essentially 

 different. 



Nests, &c., of an Earth-mason Caterpillar. 



It does not indeed require very minute observation to 

 perceive, that every grain of earth in the structure is 

 united to the contiguous grains by threads of silk ; and 

 that consequently, instead of the whole having been done 

 at once, it must have required very considerable time and 

 labour. Thi^ construction is rendered more obvious by 

 throwing one of these earthen cases into water, which 

 dissolves tlie earth, but does not act on the silk which 

 binds it together. To understand how this is performed, it 

 may not be uninteresting to follow the little mason from 

 the beginning of his task. 



When one of those burrowing caterpillars has done feed- 

 ing, it enters the earth to the depth of several inches, till 

 it finds mould fit for its purpose. Having noAvhere to throw 

 the earth which it may dig out, the only means in its power 

 (jf forming a cavity is to press it with its body ; and, by 



