This outside work is performed with measured movements and solemn diligence. The insect stands high on its legs, with its abdomen stretched at the end of its long pedicle, and turns round slowly, pivoting its whole body stiffly, with the geometrical rigidity of a line revolving on itself. If it wishes to fling to a distance the rubbish which it thinks will be in the way, it does so in short silent flights, often backwards, as though the Wasp, emerging from her well head last, avoided turning, so as to save time. It is the species carrying their abdomens on the longest stalks, such as the Sandy Ammophila and the Silky Ammophila, which mainly display this automaton-like rigidity in action. That belly swelling into a pear at the end of a thread is in fact a very delicate thing to steer: a sudden movement might warp the fine stalk. So we must walk with a sort of geometrical rigour; if we have to fly, we will do so backwards, to avoid tacking too often. On the other hand, the Hairy Ammophila, who has a short abdominal pedicle, works at her burrow with the heedless, nimble movements which we admire in most of the Digger-wasps. She has more freedom of action, because her belly does not get in her way. The home is dug. At a later hour in the day, or even merely when the sun has left the place where the burrow has just been bored, the Ammophila invariably visits the little heap of stones placed in reserve during the excavating, with the object of choosing a bit to suit her. If there is nothing that satisfies her needs, she explores the neighbourhood and soon discovers what she wants, a small flat stone slightly larger in diameter than the mouth of her hole. She carries off this slab in her mandibles and lays it, as a temporary door, over the opening of the burrow. To-morrow, when the weather is once more hot and the sun bathes the slopes and encourages hunting, the Wasp will know quite well how to find her home, rendered inviolable by the massive door; she will come back with a paralysed caterpillar, grasped by the skin of its neck and dragged between its captor’s legs; she will lift the slab, which nothing distinguishes from other little stones around and which she alone is able to identify; she will let down the game to the bottom of the well, lay her egg, and close the house for good by sweeping into the perpendicular shaft all the rubbish which she has kept in the vicinity.