"Then she flies away to find food to store up for her children. These babies like tender, green inch-worms, so Mrs. Digger-Wasp hunts around until she finds a fat one, and then proceeds to paralyze it, so that it will stay quietly in the house until the babies are ready to eat it, for baby digger-wasps are little cannibals, preferring living caterpillars to any pre-digested spiders or flies. It is very wonderful that Mrs. Digger-Wasp knows where to sting a caterpillar in order to paralyze it and yet not kill it. But she does. Perhaps you remember that insects have knots of nerve cells, connected by nerve threads, extending from one end of the body to the other? Jimmie remembers that I pinched him to illustrate this point. The knot on the top of the food-tubes is the brain, then underneath there are usually three in the thorax and several in the abdomen. Well, Mrs. Digger-Wasp stings one or more of these little knots, which we call ganglia. That paralyzes the young inch-worm, so that it becomes limp and helpless, but still lives. Then Mrs. Wasp picks it up and carries it to her house, and packs it in the bottom of the tunnel. "After putting in five or ten she lays an egg, fastening it on the body of one of the worms. She backs out of the tunnel, and flies off to collect balls of dirt. With these she fills up the tunnel completely. Carefully she puts the little round door on. One day some one saw her do a curious thing. She wished to be very sure that the door was fast shut. Perhaps it did not fit well. So she found a tiny pebble, held it in her jaws, and hammered the door down with it. Wasn't that a clever thing for a wasp to do? The door closed, this is all the attention she gives to baby digger-wasps. She has put in plenty of food, even for the hungriest larva. Now it must look out for itself, eat, grow fat and strong, and then dig its way out into the salt-marsh. "Mrs. Eumenes is a good-looking little wasp dressed in black and yellow. She is a mason, making a pretty mud vase for a home. The clay, or mud, she moistens, then moulds it, little by little, into the vase, which she fastens on to a twig. Some mud-daubers make small cylinders placed side by side. Into these they put stung spiders, after tearing off their legs to make sure they will not recover and run away before the eggs hatch. Sometimes the mud-daubers plaster up the keyholes in a house, and so have snug homes.