HABITATIONS OF INSECTS. 481 



assuming the form of a pyramid, truncated at one-third 

 of its height*: and Stedman, when in Surinam, once 

 passed ant-hills six feet high, and at least one, hundred 

 feet in circumference''. 



The nest of Formica hrunnea^ Latr. is composed 

 wholly of earth, and consists of a great number of 

 stories, sometimes 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 gal- 

 leries which preserve the communication between both. 

 The arched roofs of the most spacious rooms are sup- 

 ported by very thin walls, or occasionally by small pil- 

 lars and true buttresses ; some having only one en- 

 trance 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 car- 

 ried 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 archi- 

 tecture. Different labourers convey sxnall masses of 

 this ductile material between their mandibles, and 

 with the same instruments they spread and mould it to 

 their will, the antennae accompanying every movement. 

 They render all firm by pressing the surface lightly 

 with their fore feet : and however numerous the masses 



" Huber, Rtcherehes sur hs Mcciirs des Fuunnis, p. 16S. 

 ** Stedman's iS((/(»a»!, i. 169. 

 VOL. I. 2 I 



