HABITATIONS OF INSECTS. 477 



of numerous small apartments of different sizes, commu- 

 nicating with each other by means of galleries and ar- 

 ranged in separate stories, some very deep in the earth, 

 others a considerable height above it : the former for the 

 reception of the young in cold weather and at night, the 

 latter adapted to their use in the day time. In forming 

 these, the ants mix the earth excavated from the bottom 

 of the nest with the other materials of which the mount 

 consists, and thus give solidity to the whole. Besides 

 the avenues which joia the apartments together, other 

 galleries varying in dimensions communicate with the 

 outside of the nest at the top of the mount. These open 

 doors would seem ill calculated for precluding the ad- 

 mission of wet or of nocturnal enemies: but the ants alter 

 their dimensions continually according to circumstances; 

 and they wholly close them at night, when all gradually 

 retire to the interior, and a few sentinels only are left to 

 guard the gates. On rainy days, too, they keep them 

 shut, and when the sky is cloudy open them partially*. 

 The habitations of these ants are much larger than 

 those of any other species in this country, and sometimes 

 as big as a small haycock ; but they are mere molehills 

 when compared with the enormous mounds which other 

 species apparently of the same family, but much larger, 

 construct in warmer climates. Malouet states, that in 

 the forests of Guiana he once saw ant-hills whiclr, though 

 his companion would not suffer him to approach nearer 

 than forty paces for fear of his being devoured, seemed 

 to him to be fifteen or twenty feet high, and thirty or 

 forty in diameter at the base, assuming the form of a py- 

 =* Huber, Recherches sur les JlLvur.f des Foitrmis, p. 21-29. 



