HABITATIONS OF INSECTS. 479 



nected by no glutinous material, they appear when finish- 

 ed one single layer well united, consolidated, and smooth- 

 ed. Having traced the plan of their structure, by placing 

 here and there the foundations of the pillars and parti- 

 tion-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 spec- 

 tacle than one of these cities while building. In one 

 place vertical walls form the outline, which communi- 

 cate with different corridors by openings made in the 

 masonry; in another we see a true saloon whose vaults 

 are supported by numerous pillars ; and further on are 

 the cross ways or squares where several streets meet, and 

 whose roofs, though often more than two inches across, 

 the ants are under no difficulty in constructing, begin- 

 ning the sides of the arch in the angle formed by two 

 walls, and extending them by successive layers of clay 

 till they meet ; while crowds of masons arrive from all 

 parts with their particle of mortar, and work with a re- 

 gularity, harmony, and activity, which can never enough 

 be admired. So assiduous are they in their operations, 

 that they will complete a story with all its saloons, vault- 

 ed roofs, partitions and galleries, in seven or eight hours. 

 If they begin a story, and for want of moisture are un- 

 able to finish it, they pull down again all the crumbling 

 apartments that are not covered in a . 



Another species of ants (F. jusca) are also masons. 

 When they wish to heighten their habitations, they be- 

 gin by covering the top with a thick layer of clay which 



a Huber, RechercJies, &c, 30-40. 



