applying earth more or less mixed with chopped hay against the walls which are to support the edifice. At the summit of the construction a hole is left for entry and exit. During the whole of its sojourn in our country the swallow uses this dwelling, and even returns to it for many years in succession, as long as its work will support the attacks of time. The faithful return of these birds to their old nest has been many times proved by attaching ribbons to their claws; they have always returned with the distinctive mark.
Masons Working in Association.—Ants have already furnished us with numerous proofs of their intelligence and their prodigious industry. So remote from man from the anatomical point of view, they are of all animals those whose psychic faculties bring them nearest to him. Sociable like him, they have undergone an evolution parallel to his which has placed them at the head of insects in the same way as he has become superior to all other mammals. The brain in ants, as in man, has undergone a disproportionate development. Like man, they possess a language which enables them to combine their efforts, and there is no human industry in which these insects have not arrived at a high degree of perfection. If in certain parts of the earth human societies are superior to those of ants, in many others the civilization of ants is notably superior. No village of Kaffirs can becompared to a palace of the Termites. The classifications separate these insects (sometimes called "white ants") from the ants, since the latter are Hymenoptera, while the former are ranked among the Neuroptera, but their constructions are almost alike, and may be described together. These small animals, relatively to their size, build on a colossal scale compared to man; even our most exceptional monuments can not be placed beside their ordinary buildings. (Fig. 8.) The domes of triturated and plastered clay which cover their nests may rise to a height of five metres; that is to say, to dimensions equal to one thousand times the length of the worker. The Eiffel Tower, the most elevated monument of which human industry can boast, is only one hundred and eighty-seven times the average height of the worker. It is three hundred metres high, but to equal the Termites' audacity it would have to attain a height of sixteen hundred metres.
The lofty nest, or Termitarium, constitutes a hillock in the form of a cupola. The interior arrangement is very complicated, and at the same time very well adapted to the life of the inhabitants. There are four stories in all, covered by the general exterior walls. The walls of the dome are very thick; at the base they measure from sixty to eighty centimetres. The clay, in drying, attains the hardness of brick, and the whole is very coherent. The sentinels of herds of wild cattle choose these tumuli as ob-