PLATE XXV1. Common Swift2. Ghost Swift, male3. Ghost Swift, female
PLATE XXV
1. Common Swift2. Ghost Swift, male3. Ghost Swift, female
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 woodsswinging, 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.
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.
The wings of the female, however, are yellowish-brown, with darker markings, so that she is not nearly so ghost-like as her mate. You may sometimes see her flying slowly to and fro in the dusk, and as she does so she keeps on dropping her eggs, which fall to the ground below. After a short time they hatch, and out come a number of little dirty white caterpillars, which burrow down into the soil, and feed on the roots of burdock, stinging-nettle, and dumb-nettle, and sometimes on those of hops.