This is a little picture of Spinipes bringing up a grub, which she is clasping beneath her body
We will take Spinipes first.
If you look at the picture on the opposite page, you will see what she is like, and, if you look at the picture in Spinipes the Sand-Wasp (p. 151) you will see one of the clever things she does.
She is building a little tube out of sand which is so delicate that the slightest touch from one of our own clumsy fingers will knock it down like a card-house, but it is strong enough for her to crawl inside; and she has to crawl inside very often, as you will see. I expect you will all want to know how she builds it, and what it is for. I will tell you how she builds it to begin with. You must know first that she has a pair of jaws which work quite differently from ours. Instead of moving up and down, they move across each other from side to side just like a pair of scissors.
This is the Spinipes' grub feeding on the little green caterpillars
The first thing that Spinipes does is to work this little pair of scissors in the sand so as to make a little hole. I am showing you on page 148 a picture of her when she is just starting to dig. Every little pellet of sand she digs out she puts carefully round the outside of the hole, and presently she glues them all together. She carries the glue somewhere inside her, and brings it out when she wants it, Then she digs a little deeper and glues another layer of sand pellets on the top of the first one, and in a very short time she has dug a hole about two inches deep, and built a little tube round the top of it, which is made of the little sand-pellets she has brought out of the hole. Sometimes the tube stands straight up, but more often it bends about half-way and curves downwards. When she has finished it off, and is sure that the hole is deep enough, and the tube is long enough, she goes right down to the bottom and lays an egg, and she hangs the egg by a tiny thread (which she also makes herself, but I don't know how she does it) to the side of the hole a little above the bottom. You will be able to see this in the picture, but you must remember that in this and in some of the other pictures the sand has been cut away so that you can see exactly how the hole goes. Then, if it is a bright, sunny day, as it usually is when she begins digging, she flies away, and in about half an hour's time comes back carrying something clasped tight against her body. What do you think that is? It is a small green caterpillar. She stops a moment at the entrance of the tube, pushes the caterpillar down in front of her, and disappears after it. In a few seconds she is out again and off, and in another quarter of an hour or so she is back again with another caterpillar and so on, without ever tiring, through six or seven hours of a hot June or July day.
This shows you the cocoon which Spinipes' grub makes for itself. I have opened it to show you the grub, and also the little partition in the shaft above the grub, which is the last thing Spinipes herself makes
I expect you will have guessed what the caterpillars are for. They are food for the wasp grub when it hatches out of the egg. Generally each hole has between twenty and thirty little caterpillars in it, and sometimes, when caterpillars are scarce, the Mother Wasp has to work hard for three or four days. If you dig into a hole yourself and look at the store of little caterpillars, you will see there is something the matter with them. They seem to be alive and yet they don't seem to be able to crawl. Wise men say that the wasp stings them just enough to make them drowsy so that they can't crawl out of the hole, and can't hurt the wasp grub by jostling up against it. It wouldn't do to kill them, because then they would go bad in the hole before the grub had time to eat them. This sounds rather cruel, but I don't think it is really, because it is quite certain that the caterpillars cannot feel as we should perhaps feel, and we may be quite sure that in the wonderful Nature World everything is arranged for the best, so that only the right number of wasp-grubs may be properly fed and grow up to do what it is their duty to do, and only the right number of small green caterpillars may grow up also.