At 12 a friend was carried to the nest. 12.20 a stranger was dropped into the water. 12.40 a stranger was dropped into the water. 2.30 a stranger was dropped into the water. Of Thus, then, the general results were that the ants removed forty-one friends and fifty-two strangers. the friends, thirty-two were carried into the nest and nine were thrown into the water. Of the strangers, on the contrary, forty-three were thrown into the water; only nine were taken into the nest, and seven of these were shortly afterwards brought out again and thrown away. Indeed, I fully believe that the other two were treated in the same manner, though we could not satisfy ourselves of the fact. But it was only by very close observation that the seven were detected, and the other two may well have escaped notice. It seems clear, therefore, that even in a condition of insensibility these ants were recognised by their friends. Tabular View.-Experiments on Ants under In these cases some of the Ants had partly recovered; in the following they were quite insensible. 119 CHAPTER VI. RECOGNITION OF FRIENDS. IT has been already shown that with ants, as with bees, while the utmost harmony reigns between those belonging to the same community, all others are enemies. I have already given ample proof that a strange ant is never tolerated in a community. This of course implies that all the bees or ants of a community have the power of recognising one another, a most surprising fact, when we consider the shortness of their life and their immense numbers. It is calculated that in a single hive there may be as many as 50,000 bees, and in the case of ants the numbers are still greater. In the large communities of Formica pratensis it is probable that there may be as many as from 400,000 to 500,000 ants, and in other cases even these large numbers are exceeded. If, however, a stranger is put among the ants of another nest, she is at once attacked. On this point I have satisfied myself, as will be seen in the following pages, that the statements of Huber and others are perfectly correct. If, for instance, I introduced a stranger into one of my nests, say of Formica fusca or Lasius niger, she was at once attacked. One ant would seize her by an antenna, another by a leg, and she was either dragged out of the nest or killed. Moreover, we have not only to deal with the fact that ants know all their comrades, but that they recognise them even after a lengthened separation. Huber mentions that some ants which he had kept in captivity having accidentally escaped, 'met and recognised their former companions, fell to mutual caresses with their antennæ, took them up by their mandibles, and led them to their own nests; they came presently in a crowd to seek the fugitives under and about the artificial ant-hill, and even ventured to reach the bell-glass, where they effected a complete desertion by carrying away successively all the ants they found there. In a few days the ruche was depopulated. These ants had remained four months without any communication.'1 This interesting statement has been very naturally copied by succeeding writers. See, for instance, Kirby and Spence's 'Introduction to Entomology,' vol. ii. p. 66, and Newport, 'Trans. of the Entomological Society of London,' vol. ii. p. 239. Forel, indeed, regards the movements observed by Huber as having indicated fear and surprise rather than affection; though he is quite disposed to believe, from his own observations, that ants would recognise one another after a separation of several months. 1 Huber, p. 172. The observation recorded by Huber was made casually, and he did not take any steps to test it by subsequent experiments. The fact, however, is of so much importance that I determined to make further observations on the subject. In the first place, I may repeat that I have satisfied myself by many experiments, that ants from one community introduced into another, always be it understood of the same species, are attacked, and either driven out or killed. It follows, therefore, that as within the nest the most complete harmony prevails—indeed, I have never seen a quarrel between sister ants—they must by some means recognise one another. When we consider their immense numbers this is sufficiently surprising; but that they should recognise one another, as stated by Huber, after a separation of months, is still more astonishing. I determined therefore to repeat and extend his observations. Accordingly, on August 20, 1875, I divided a colony of Myrmica ruginodis, so that one half were in one nest, A, and the other half in another, B, and were kept entirely apart. On October 3, I put into nest B a stranger and an old companion from nest A. They were marked with a spot of colour. One of them immediately flew at the stranger; of the friend they took no notice. October 18.-At 10 A.M. I put in a stranger and a |