110 NATURAL HISTORY. [CH. VI. 



ture did not trust to its teeth alone ; but first voided 

 a liquid drop on the spot, and by this means soft- 

 ened the material which it wanted for use. Then 

 having recourse to its teeth, it detached a morsel 

 from the mass, and taking it up in its two fore-legs, 

 kneaded it into a mortar. With such materials, and 

 so gathered, the insect commences its operations. 



In the following figure several tubes are seen 

 jutting out of the mass ; although formed with great 

 care and art, and evidently manifesting design, they 

 are not made to last ; they are no more than tem- 

 porary elevations raised over the excavation in the 

 wall or sand, and are destined to be destroyed as 

 soon as the latter is completed. 



o, &, c, d, e, exhibit the formation of the tubes in various stages. 



The little pieces of moistened sand and earth first 

 gathered, are placed in a circle, which serves to 

 mark out the dimensions of the hole. As the in- 

 sect continues to dig, it adds to the length of the 

 tube, and when it has completed the excavation, it 



