The Skylark, so common in almost every part of France, does not nest in the Vaucluse plains, where his place is taken by the Crested Lark, that frequenter of the broad highway, the roadmender’s friend. But one need not go far north to find the favourite spots for the Skylark’s broods: the next department, the Drôme, is rich in his nests. It is very probable therefore that, out of the numbers of Skylarks that come to take possession of our plains for the whole of autumn and winter, there are many that travel no farther than the Drôme. They have only to migrate to the next department to find plains free from snow and a steady supply of tiny seeds. A like migration to a short distance seems to me to have caused the crowd of Ammophilæ which I surprised near the top of Mont Ventoux. I have shown that this Wasp spends the winter in the perfect insect state, hidden in some shelter and waiting until April to make her nest. She also, like the Skylark, must take her precautions against the frosty season. Though she need not fear the lack of food, being capable of fasting until the return of the flowers, she must at least, delicate creature that she is, guard against the fatal attacks of the cold. She will therefore flee snowy country, the districts where the ground freezes to a great depth; she will assemble in a migratory caravan, after the manner of the birds, and, crossing hill and dale, will select a home in old walls and sandy banks warmed by the southern sun. Then, when the cold is past, all or part of the troop will return to the place whence they came. This would explain the Ventoux band of Ammophilæ. It was a travelling tribe which, coming from the cold uplands of the Drôme and descending into the warm plains beloved of the olive-tree, had crossed the wide, deep valley of the Toulourenc and, when surprised by the rain, had called a halt on the mountain-ridge. Apparently, therefore, the Hairy Ammophila has to migrate in order to escape the cold of winter. At the time when the little birds of passage start their procession of caravans, she too journeys from a colder to a warmer neighbourhood. She has but to cross a few valleys and a few mountains to find the climate which she wants. I have two other instances of extraordinary gatherings of insects at great heights. In October I have found the chapel at the summit of Mont Ventoux covered with Coccinella septempunctata, the Seven-spot Ladybird. The insects clinging to the stone of both the roof and walls were packed so close together that the rude edifice looked, from a little way off, like a piece of coral-work. I should not care to guess the myriad numbers of the Ladybirds collected there. Those Aphis-eaters had certainly not been attracted by the hope of food to the top of the Ventoux, some 6000 feet above the level of the sea. Vegetation is too scanty up there; and no Plant-louse ever ventured so high.