ANTS BOARDED BY TREES 



spines instead of stipules at the base of the leaf. It is in- 

 side these spines that the troops of the police-insects live. 

 These Acacias (Oxhorn Acacia, as well as A. sphcerocephala 

 and A. spadicigera) also produce sugar, which is secreted by 

 peculiar gland-like organs on the stalks of the leaves, and 

 even albuminoids, for at the tips of the leaflets there are 

 peculiar little bodies which contain albuminous matter. 



The Imbauba tree (Cecropia spp.) also possesses a 

 standing army of these ants. It puts them up in the hollow 

 pith in the centre of the tree, which is divided into large 

 roomy spaces and makes a convenient nest. There is a 

 minute opening by which they run in and out. On one 

 occasion a naturalist found that the ants had been benumbed 

 by a period of very cold weather, and in consequence had 

 neglected their duty, and the trees had been stripped of their 

 leaves by leaf-cutting kinds.^ 



These last mentioned, the leaf-cutting ants, are especially 

 dreaded by owners of plantations. Foreign or introduced 

 plants are not specially guarded against their ravages by 

 special secretions, as is the case with the native flora, so that 

 the coffee and cocoa plantations are often severely injured. 

 In some places man has copied those Acacias and 

 Imbaubas, for in the orange plantations of the province of 

 Canton, in China, ants' nests are collected and placed on the 

 trees. Moreover, the different trees are connected together 

 by bamboos, so that the ants can easily pass, as on a bridge, 

 from one tree to another. 



Near Mantua, in Italy, the same system seems to be adopted, 



and ants' nests are carefully placed near the fruit trees. 



Their use can be quite well understood, for Forel, in his 



work on the Ants of Switzerland, estimates that one ants'" 



^ Belt, Natv/ralist in Nicaragiui. 



287 



