And this upside-down position, which seems to us so trying, lasts for no short while. It continues, in my cages, for ten months without a break. The Fly on the ceiling, it is true, adopts the same position; but she has her moments of rest. She flies, she walks in the usual way, she spreads herself flat in the sun. The Empusa, on the other hand, remains in her curious attitude for ten months on end, without a pause. Hanging from the wire netting, back downwards, she hunts, eats, digests, dozes, gets through all the experiences of an insect’s life, and finally dies. She clambers up while she is still quite young; she falls down in her old age, a corpse. This custom is all the more remarkable in that it is practised only in captivity. It is not an instinctive habit of the race; for out of doors the insect, except at rare intervals, stands on the bushes back upwards. Strange as the performance is, I know of a similar case that is even more peculiar: the attitude of certain Wasps and Bees during the night’s rest. A particular Wasp, an Ammophila with red fore-legs, is plentiful in my enclosure towards the end of August, and likes to sleep in one of the lavender borders. At dusk, especially after a stifling day when a storm is brewing, I am sure to find the strange sleeper settled there. Never was a more eccentric attitude chosen for a night’s rest. The jaws bite right into the lavender-stem. Its square shape supplies a firmer hold than a round stalk would give. With this one and only prop the Wasp’s body juts out stiffly at full length, with legs folded. It forms a right angle with the stalk, so that the whole weight of the insect rests upon the mandibles. The Ammophila is enabled by its mighty jaws to sleep in this way, extended in space. It takes an animal to think of a thing like that, which upsets all our previous ideas of rest. Should the threatening storm burst and the stalk sway in the wind, the sleeper is not troubled by her swinging hammock; at most, she presses her fore-legs for a moment against the tossing stem. Perhaps the Wasp’s jaws, like the Bird’s toes, possess the power of gripping more tightly in proportion to the violence of the wind. However that may be, there are several kinds of Wasps and Bees who adopt this strange position,—gripping a stalk with their mandibles, and sleeping with their bodies outstretched and their legs folded back. This state of things makes us wonder what it is that really constitutes rest.