On the other hand, when performing like experiments with _Lasius flavus_, it took the ants (on two occasions) some little time to recognize their kindred; when the marked ants were put into the nest they were at once seized by the other ants, which pulled them about the nest for some time. They were finally recognized, however, and the paint removed from their bodies by the busy little tongues of their kindred.
This would seem to indicate that _Lasius niger_ had a better memory than _Lasius flavus_; whether the failure of the latter to recognize their friends at once was due, however, to faulty memory or not, is a psychical problem that will, probably, never be solved.
Lubbock's experiments with _Myrmica ruginodis_ clearly demonstrate that these ants can recognize their kin. Says he:--
"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 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]