Lastly, Sir John Lubbock made some experiments with the express purpose of testing the power of communication by ants. He found that if an ant discovered a deposit of larvæ outside the nest, she would return to the nest, and, even though she might have no larvæ to show, was able to communicate her need of assistance—a number of friends proceeding to follow her as a guide to the heap of larvæ which she had found. In one very instructive experiment Sir John arranged three parallel pieces of tape, each about two and a half feet long: one end of each piece of tape was attached to the nest, and the other dipped into a glass vessel. In the glass at the end of one of the tapes he placed a considerable number of larvæ (300 to 600): in the glass at the end of another of the pieces he put only two or three larvæ, while the third glass he left empty. The object of the empty glass was to see whether any of the ants would come to the glass under such circumstances by mere accident. He then took two ants, one of which he placed in the glass with the many larvæ, and the other in the glass with the few. Each ant took a larva, carried it to the nest, then returned for more, and so on. After each journey he put another larva in the glass with the few larvæ, in order to replace the one which had been removed. The result of the experiment was that during 47½ hours the ants which had gone to the glass containing numerous larvæ brought 257 friends to their assistance, while during 53 hours those which had gone to the glass containing only two or three larvæ brought only 82 friends; and no single ant came to the glass which contained no larva. Now, as all the glasses were exposed to similar conditions, and as the roads to the first two must, in the first instance at all events, have been equally scented by the passage of ants over them, these results appear very conclusive as proving some power of definite communication, not only that larvæ are to be found, but even where the largest store is to be met with. As to the means of communication, or method of sign-making, there can be no doubt that this in ants, as in bees, is mainly gestures made by the antennæ; but that gestures of other kinds are also employed is sufficiently well proved by the following observation of the Rev. Dr. M’Cook. “I have seen an ant kneel down before another and thrust forward the head, drooping quite under in fact, and lie there motionless, thus expressing as plainly as sign-language could, her desire to be cleansed. I at once understood the gesture, and so did the supplicated ant, for she at once went to work.” So much, then, for the power of sign-making displayed by the Hymenoptera. As I have not much evidence of sign-making in any of the other Invertebrata,[62] I shall pass on at once to the Vertebrata.