Now when we come to insects, we find that the above inferences do not hold. It has been observed that when a solitary wasp finds its hole in the ground too small to admit the spider or other insect which it has brought, it falls to and enlarges it. In this and in other respects certain insects seem to take the step of reason that quadrupeds are incapable of. Lloyd Morgan relates at some length the experiments he tried with his fox terrier, Tony, seeking to teach him how to bring a stick through a fence with vertical palings. The spaces would allow the dog to pass through, but the palings caught the ends of the stick which the dog carried in his mouth. When his master encouraged him, he pushed and struggled vigorously. Not succeeding, he went back, lay down, and began gnawing the stick. Then he tried again, and stuck as before, but by a chance movement of his head to one side finally got the stick through. His master patted him approvingly and sent him for the stick again. Again he seized it by the middle, and of course brought up against the palings. After some struggles he dropped it and came through without it. Then, encouraged by his master, he put his head through, seized the stick, and tried to pull it through, dancing up and down in his endeavors. Time after time and day after day the experiment was repeated with practically the same results. The dog never mastered the problem. He could not see the relation of that stick to the opening in the fence. At one time he worked and tugged three minutes trying to pull the stick through. Of course, if he had had any mental conception of the problem or had thought about it at all, a single trial would have convinced him as well as would a dozen trials. Mr. Morgan tried the experiment with other dogs with like result. When they did get the stick through, it was always by chance. It has never been necessary that the dog or his ancestors should know how to fetch long sticks through a narrow opening in a fence. Hence he does not know the trick of it. But we have a little bird that knows the trick. The house wren will carry a twig three inches long through a hole of half that diameter. She knows how to manage it because the wren tribe have handled twigs so long in building their nests that this knowledge has become a family instinct.