"On October 3, I put into nest B a stranger and an old companion from nest A. They were marked with a spot of color. 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 friend from nest A. In the evening the former was killed, the latter was quite at home. "October 19.--I put one in a small bottle with a friend from nest A. They did not show any enmity. I then put in a stranger, and one of them immediately began to fight with her."[37] [37] Lubbock, _Ants, Bees, and Wasps_, p. 121 _et seq._ These experiments show that _Myrmica ruginodis_ recognize their kin at sight, and that they are able to remember and recognize one another after long separations. Lubbock states that _Lasius flavus_ accept others of the same species as their friends, no matter how great a distance lies between the nests. His experiments were made with ants taken from contiguous nests as well as those located some distance apart, and, in one instance, with ants taken from a nest in another part of the country. He states that, in the last-mentioned experiment, "in one or two cases they seemed to be attacked, though so feebly that I could not feel sure about it; but in no case were the ants killed."[38] [38] Lubbock, _loc. cit. ante_, p. 124. My experiments and observations with this ant are directly the reverse. As long as the individuals experimented with belonged to contiguous nests, and were, probably, derived from the same root-stock, there was no fighting; but, in the case of ants taken from opposite sides of the house, which, probably, sprang from two different sources, there was, invariably, much fighting, in which not a few of the combatants lost their lives. Whether or not the American species of _Lasius flavus_ are naturally more pugnacious than the English species, I know not; if they are, then this fact will account for the difference in behavior of the two species to a certain extent, though not entirely. Others of the social Hymenoptera--for instance, bees and wasps--remember kindred. On one occasion, I clipped the wings of a wasp, and, after she had learned that she could no longer fly, placed her on a strange nest. She was at once attacked, and was soon stung to death. I kept a wasp confined in a glass for three weeks, carefully feeding her meanwhile, and then placed her on the nest from which she had been taken. She was at once recognized by the other wasps, which caressed her with their antennæ, and licked her with their tongues. Bees, though they seem able to recognize kindred, and to remember them also for some time, do not show these faculties of the mind as plainly as do wasps and ants. This is probably due to the fact that bees are a later development, socially speaking, and are not as psychically mature as the other social insects.