lO Bulletin American Museum of Natural History. [Vol. XXII, 



It was a little chamber with vaulted, smooth, and continuous walls. 

 The ants had taken advantage of the form of the plant, suspending 

 their edifice so that the stem passed through its center while the 

 leaves formed its only scaffolding. This retreat enclosed a numerous 

 family of plant-lice to which the brown ants were peacefully resorting 

 for the purpose of feeding on their ejecta in a shelter from the rain, 

 sun, and alien ants. No insect could molest them, and the plant-lice 

 were protected from their numerous enemies. . . . 



"Several spurge stems laden with plant-lice rose from the very 

 midst of a formicary of brown ants. These, profiting by the peculiar 

 arrangement of the leaves of this plant, had built around each branch 

 as many elongated chambers, to which they repaired in search of 

 food. .When I destroyed one of these domiciles, the ants straightway 

 carried their precious animals into their nest. A few days later the 

 structure was repaired by the insects under my very eyes and the 

 herds were brought back to their pasture. 



"These tents are not always so near the earth. I have seen one 

 five feet above the ground, and this one merited a description. It 

 consisted of a blackish, rather short tube surrounding a small poplar 

 branch where it left the trunk. The ants entered it from the hollow 

 interior of the tree in such a way that, without exposing themselves, 

 they could reach their plant-lice by means of an opening at the very 

 base of the branch. The tube consisted of rotten wood from the tree 

 itself, and I saw the ants repeatedly bringing particles in their jaws 

 in order to repair the breaches I made in their pavilion. This par- 

 ticular act is not very common and is not one that can be attributed 

 to the routine of habit. 



"There are also some ants that obtain their food from the plant- 

 lice on the common plantain. These insects are usually stationed 

 under the flower spike, but when this has faded and the stem begins 

 to wither — and this occurs towards the end of August — the aphides 

 retire beneath the root-leaves of the plant. Thither they are followed 

 by the ants, which cloister themselves with their protegees by walling 

 up with damp earth all the openings between the edges of the leaves 

 and the ground. Then they excavate the earth underneath, in order 

 to gain access to the aphides and be able to pass from them to their 

 nest through covered galleries." 



Ruber's observations have been confirmed by Forel,^ who has 

 shown that in Europe tents are constructed by various species of 

 Lasius (niger. aUenus, brunneus, and emarginatus) and Myrmtca 



' Les Fourmis de la Suisse. Zurich, 1874, pp. 204, 205. 



