Neither can it, when it, all at once, comes off its stalk and begins to fly about, in the shape of a butterfly, which is what happens, sometimes, in India and the Malay Archipelago, as we shall immediately see. In these countries there is a butterfly that belongs to the same family as our own purple emperor, and, as far as the upper surface of its wings is concerned, it is a purple emperor, and so looks like one, when it flies. But as soon as it settles, it becomes a leaf, for then it raises its wings above its back, in the way butterflies do, so that only their under surface is seen, which is as like a dry brown leaf as anything that is not one can be. The shape is exact, from the extreme point, or tip, of the upper wing, to the little swallow tail at the end of the lower one, which last just touches the stem that the butterfly clings on, and makes the stalk of the leaf. Between the tip and the stalk there runs a well-marked dark line, which answers very well for the leaf’s mid-rib, whilst on each side of it thinner lines are traced, representing the lateral veins. The slender legs of the butterfly, as it sits on the stalk, are hardly to be seen, and its head lies just hidden between the margins of the wings. The leaves of the bush on which it has gone down are of the same shape and colour as itself, for it takes care not to settle amidst surroundings with which it would not be in harmony. A bird, therefore, that has pursued this brilliant blue butterfly into a bush, where it disappears, is completely baffled; and so, too, is a grave scientific gentleman with a butterfly-net in his hand.