The Peckhams, too, saw an Ammophila in Wisconsin use a pebble as a tool, and what is especially interesting and important, this wasp was only a single individual of several others watched by the observers, all these wasps being of one kind, that is, belonging to the same species. The tool-user thus revealed an individuality that made its actions seem to be dictated by something else than rigid instinct; certainly so if instinct is to be defined as untaught and unreasoned behavior common to all the individuals of a kind. In fact the Peckhams (most persistent, practised and intelligent observers) insist that "in all the processes of Ammophila the character of the work differs with the individual." But where is Mary in all this digression of mine? Never fear for Mary. While I was mumbling about instinct and reason and automatism and individual idiosyncrasy, Mary was crawling slowly and cautiously about over the salt-crust floor of our room, counting the wasp holes in course of making, and she was making a second discovery. The measuring-worms, limp and lifeless as they appeared, were really not dead! She had seen at least two, left lying on the ground by the hole while the wasp prized off the cover, give feeble wriggles, and one that she poked with a pin squirmed rather energetically. That is, it did if she poked it at one end, but not if she poked it in the middle, which is such a great discovery that it really gets to be science! Now as one is entitled to take violent measures for the sake of science, Mary and I decided after considerable serious discussion to "collect" the hole which our wasp had finished and apparently left for good. So we dug it up, and on the spot we examined it and all of its insides. And we found it quite true that the loopers were not dead, but they were _paralyzed_! When we poked a head or tail, each worm could squirm just a little, but if we touched them in the middle, they didn't know it, and on one of them, the top one, we found a little shining white speck. Mary's excitement became merged into an intense thoughtfulness. Then she cried aloud with eyes shining: "My, it's the egg! the egg of the wasp! and the worms are for food for the young wasp when it hatches!" Ah, Mary, you have wits! Have you ever heard any one tell about this? Did you really guess it, or not guess it, but actually reason it out for yourself? Mary, I have great hopes of you.