This is the largest of all the British “clearwings,” and it really does look so very much like a hornet that most people would be quite afraid to meddle with it for fear of being stung. But if ever you should happen to meet with the moth you can tell it from a real hornet quite easily; for if you look closely at it you will see that its body is not smooth and shiny, but is covered all over with close, soft down. The best place to look for it is on the trunks of poplar trees, quite close to the ground, in June and July; for after it comes out of the chrysalis it always sits on the tree-trunk for some little time in order to dry its wings. And you will nearly always find that it is sitting quite close to the burrow which it made when it was a caterpillar, and in which it lived for no less than two whole years. There is another kind of “hornet clearwing,” whose caterpillar feeds in the stems of osiers instead of in the trunks of poplar trees. But it is not at all a common insect, and you are not very likely ever to find it. [Illustration: PLATE XXV 1. Common Swift 2. Ghost Swift, male 3. Ghost Swift, female] PLATE XXV THE COMMON SWIFT (1) The “swift” moths owe their name to their rapid flight, for they can all fly very swiftly indeed when they are alarmed. But very often, on a warm summer’s evening, you may see them in grassy places in woods _swinging_, as it were, in the air--flying first a foot or so to one side, and then a foot or two to the other side, over and over again, just like the pendulum of a clock. And when they are doing this they do not seem at all ready to take the alarm, so that you can easily catch them. Five kinds of these moths are found in the British Islands, of which the Common Swift is by far the most plentiful. It lives, not only in woods, but also in lanes and on the borders of fields, and on warm evenings in June you may see it darting swiftly along almost any hedgerow. And if you catch a dozen or so you will find that the males are all spotted and streaked with white, while the females are plain dingy brown all over. And, besides that, you will see that no two of the males are quite alike, some of them having a great many more white markings than the others. The caterpillar of this moth lives underground, and feeds on the roots of dumb-nettles. PLATE XXV THE GHOST SWIFT (2 and 3) That is rather a curious name to give to a moth, isn’t it? But the very first time that you notice the male insect flying about on a warm summer’s evening you will see why the title was given to it; for it keeps on suddenly appearing and disappearing, over and over again, just as if it had the power of making itself visible or invisible whenever it chose. The fact is that the upper surface of the wings is glossy white, while the lower is dark brown, and that as the insect flies you can see the one and not the other. So every time that the wings are lowered the moth appears; and every time that they are raised it disappears.