So we wait until the dwellers are ready to come out. Or if occasionally we really think we ought to see how things are going on inside, we chop a house or two open and see what we can see. What this is, usually, is a house's insides very unusual and curious, for the rooms occupy so little space and the walls so much. Sometimes there is only one room and that right in the middle, all the rest of the house being just a dense or sometimes loose and spongy wall all around it. In the single room, or in each of the several rooms, we find a curled-up little shining white grub without legs, and of course without wings, and with a head that doesn't seem much like a head, for it has no eyes nor feelers, and most of the time is drawn back into the body of the grub so that it is hardly visible at all. But there is a mouth on this silly sort of head, and the grub eats. What it eats is part of its own house! The houses, or galls, as the entomologists call them, are of course not actually made by the insects that live in them; they are made by the oak-tree on which they are. But they are only made at the demand, so to speak, of the insects. That is, the oak-galls are formed only where a gall-insect has pricked a live leaf or stem or twig with her sharp, sting-like little egg-layer, and has left an egg in the plant-tissue. Nor does the gall begin to form even yet. It begins only after the young gall-insect is hatched from the egg, or at least begins to develop inside the egg. Then the gall grows rapidly. The tree sends an extra supply of sap to this spot, and the plant-cells multiply, and the house begins to form around the little white grub. Now this house or gall not only encloses and protects the insect, but it provides it with food in the form of plant-sap and a special mass or layer of soft nutritious plant-tissue lying right around the grub. So the gall-insect not only lives in the house, but eats it! After it is full-grown, the grub stops eating. Then the house, or gall, stops growing and becomes harder and changes from greenish to some other color, and, in most cases, pretty soon drops off the tree to the ground. The gall-insect is still alive inside, of course, but is perfectly quiet and is simply waiting. It is at this time in the life of the houses and their dwellers that Mary and I collect them and bring them home and put them into little tarlatan bags. This is autumn, the time that the trees in the East turn yellow and red, but in California do not. They just stay green, but get quiet or turn brown or simply drop off their leaves and stand bare.