An allied species of ant, the _Lasius brunneus_, lives almost entirely on the sweet secretion of large Aphides in the bark of oaks and walnut trees. The ants construct around these insects cabins made of fragments of wood, and wall them in completely so as to keep them at their own disposal. The _Myrmica_ also forms similar pasture lands; its system is rather less perfect than that of the _Lasius_, as it does not form covered galleries to reach its stables. It is content to build large earth huts around a colony. A large hole, which allows the passage of the ants, but not the escape of the flock, is formed so that they may come to milk their cows. They use the same methods we have seen practised on the _Claviger_, caressing the insect with their antennae until the sugared drop appears.[68] [68] In Central America, Belt has described how the Leaf-hoppers are milked for their honey by various species of Ants, and also by a Wasp. He considered that some species of Leaf-hopper would be exterminated if it were not for the protection they received from Ants.--_Naturalist in Nicaragua_, 1888, pp. 227-230. An example is quoted which shows still greater intelligence and foresight in Ants. They have been known to repopulate their territories after an epidemic, or at least after the destruction of their Aphides. The proprietor of a tree, finding it covered with these exploited beasts, cleared it of its inconvenient guests by repeated washes; but the dispossessed Hymenoptera, considering that this pasture close to their nest was very convenient for a flock, resolved to repopulate it, and for some time these tenacious insects could be seen bringing back among the foliage Aphides captured elsewhere.[69] [69] P. Huber, _Recherches_, etc., pp. 210-250; Lubbock, "On the Habits of Ants," _Wiltshire Arch. and Nat. Hist. Mag._, 1879, pp. 49-62. _Slavery among Ants._--The custom of making slaves is widely spread in the ant world; I have already described the expeditions organised to obtain them. We will now consider the relations of these insects among themselves.