HYMENOPTERA. 243 



"With respect to the Ants, Kirby and Spence give the 

 following account of the building of their habitations, 



" The nest of Formica brunnea is composed wholly of 

 earth, and consists of a great number of stories, some- 

 times not fewer than forty, twenty below the level of 

 the soil, and as many above, which last, following the 

 slope of the ant-hill, are concentric. Each story, 

 separately examined, exhibits cavities in the shape of 

 saloons, narrower apartments, and long galleries which 

 preserve the communication between both. The arched 

 roofs of the most spacious rooms are supported by very 

 thin walls, or occasionally by small pillars and true 

 buttresses ; some having only one entrance from above, 

 others a second, communicating with the lower story ; 

 the main galleries, of which, in some places, several 

 meet in one large saloon, communicate with other 

 subterranean passages, which are often carried to the 

 distance of several feet from the hill. These insects 

 work chiefly after sunset. In building their nest they 

 employ soft clay only, scraped from its bottom when 

 sufficiently moistened by a shower, which, far from 

 injuring, consolidates and strengthens their architecture. 

 Different labourers convey small masses of this ductile 

 material between their mandibles, and with the same 

 instrument they spread and mould it to their will, the 

 antenna? accompanying every movement. They render 

 all firm by pressing the surface lightly with their fore 

 feet ; and however numerous the distinct masses of clay 

 composing these walls, and though connected by no glu- 

 tinous material, they appear when finished, one single 

 layer, well united, consolidated and smoothed. Having 

 traced the plan of their structure, by placing here and 

 there the foundations of the pillars and partition- walls, 

 they add successively new portions ; and when the 

 walls of a gallery or apartment, which are half a line 

 thick, are elevated about half an inch in height, they 

 join them by springing a flattish arch or roof from one 

 side to the other. Nothing can be a more interesting 

 spectacle than one of these cities while building. In 



E 2 



