Since the Swallow, the Sparrow, and the Wasp existed before man, their industry cannot be dependent on the works of man. Each of them must have had an art of building in the time when man was not here. For thirty years and more I asked myself where the Pelopæus lived in those times. Outside our houses I could find no trace of her nests. At last chance, which favours the persevering, came to my help. The Sérignan quarries are full of broken stones, of refuse that has been piled there in the course of centuries. Here the Fieldmouse crunches his olive-stones and acorns, or now and then a Snail. The empty Snail-shells lie here and there beneath a stone, and within them different Bees and Wasps build their cells. In searching for these treasures I found, three times, the nest of a Pelopæus among the broken stones. These three nests were exactly the same as those found in our houses. The material was mud, as always; the protective covering was the same mud. The dangers of the site had suggested no improvements to the builder. We see, then, that sometimes, but very rarely, the Pelopæus builds in stoneheaps and under flat blocks of stone that do not touch the ground. It was in such places as these that she must have made her nest before she invaded our houses. The three nests, however, were in a piteous state. The damp and exposure had ruined them, and the cocoons were in pieces. Unprotected by their earthen cover the grubs had perished—eaten by a Fieldmouse or another. The sight of these ruins made me wonder if my neighbourhood were really a suitable place for the Pelopæus to build her nest out of doors. It is plain that the mother Wasp dislikes doing so, and is hardly ever driven to such a desperate measure. And if the climate makes it impossible for her to practise the industry of her forefathers successfully, I think we may conclude that she is a foreigner. Surely she comes from a hotter and drier climate, where there is little rain and no snow. I believe the Pelopæus is of African origin. Far back in the past she came to us through Spain and Italy, and she hardly ever goes further north than the olive-trees. She is an African who has become a naturalised Provençal. In Africa she is said often to nest under stones, but in the Malay Archipelago we hear of her kinswoman in houses. From one end of the world to the other she has the same tastes—Spiders, mud cells, and the shelter of a man’s roof. If I were in the Malay Archipelago I should turn over the stone-heaps, and should most likely discover a nest in the original position, under a flat stone. CHAPTER VII THE PSYCHES I A WELL-DRESSED CATERPILLAR In the springtime, those who have eyes to see may find a surprise on old walls and dusty roads. Certain tiny faggots, for no apparent reason, set themselves in motion and make their way along by sudden jerks. The lifeless comes to life: the immovable moves. This is indeed amazing. If we look closer, however, we shall solve the riddle.