There are not nearly so many butterflies as there are moths. But as the moths often fly at night, we know butterflies best, because they flutter about in the bright sunshine. Their caterpillars do not do so much harm in the garden as the moth caterpillars, except those of the Cabbage butterfly, which we read about in Book III.
You will find it very interesting, in the spring and early summer, to look for the chrysalis of each common butterfly, and keep them in a box with a piece of coarse muslin over it, so as to watch when they come out.
If you do this you will see their colours much better than by catching them, because when they first come out of their sheath, their wings are not battered with wind and rain. And you need not kill them, when you have looked at them you can set them free to enjoy the sunshine.
It is curious that so many butterflies lay their eggs on the leaves of stinging nettles. Perhaps it is because the cows and sheep will not eat these plants, so the eggs are safe. The Peacock butterfly, the small Tortoiseshell, and the Red Admiral all leave their eggs on nettles. It is there that you will find their pupas or chrysalises. Let me tell you how to know them.
The eggs of the Peacock butterfly are gummed in patches under the nettle leaves, and in June you may find the little black caterpillars spotted with white all feeding together in groups. Early in July they will each of them have spun a little cushion of silk under some leaf, by which the curious stiff chrysalis hangs head downwards, looking like a brown shining shell (3, Plate, p. 10).
If you carry home either the caterpillar (2), or the chrysalis, you will find that about the end of July a glorious butterfly (1) will come out. Its hind wings are brown and its front wings bright red and blue, and on each of the four wings there is a large bright eye-spot, like the eyes on a peacock's tail. The body is dark blue, and the feelers on the head are long and thin, with knobs at the end. But when the butterfly shuts its wings (1a), all the bright colours are hidden and the whole insect is brown like the trunk of a tree, with pale edges like wood newly cut, so that the birds are not so likely to see it when it is resting.
But, if you bring home another chrysalis from the nettles by mistake, a different butterfly will surprise you. This one has wings much notched round the edge, and they are coloured black with red markings and white spots. It is the Red Admiral, whose pupa also hangs head downwards under nettle leaves. You will not make this mistake if you find the caterpillar, for it is not black like that of the Peacock butterfly, but dark green with a yellow line on its sides, and it has spikes all over it. It feeds on nettle leaves which it ties round itself with silken threads. And you must remember that these green and yellow caterpillars will turn into Red Admirals.
Again, you may find a bunch of nettle leaves tied together with silk, which have many caterpillars inside them. These will be very spiny, and have four yellow stripes on their black bodies. They will turn into small Tortoiseshell butterflies.
Unless you know these three kinds of caterpillars well, the safe way is to bring them all home and keep them till the butterflies come out, and then notice many little differences which I cannot give you here.
On the thistles you may find another caterpillar which draws the leaves round it, and whose chrysalis has gold spots upon it. This will turn into a reddish brown butterfly called the Painted Lady. In some years there are very few of these, while in other years they are plentiful.
Our next search shall be among the alder trees by the riverside either in the early spring or about the end of July, for there are two broods of this butterfly.
You must look among the small twigs for a pretty green chrysalis with red dots on it, something like a ribbed shell. It will be tied round the middle to the stem of the twig by a fine rope of silk (5, Plate, p. 10). Notice how cleverly the caterpillar has swung it, so that the heavy broad end balances the long thin one. Then cut off the twig and take it home. The chrysalis will turn into the Brimstone butterfly (4), whose pale yellow wings have four red spots on them. You will know it quite well, for it is generally the first butterfly to come out in the spring.
Next we shall have to look low down among the plants by the roadside. There are some with white and pink flowers whose petals are in the form of a cross. They are called rockcress and bittercress, and if you can find out which they are, and look under their leaves you may find a most curious chrysalis (7, p. 10) shaped like a boat pointed at both ends. This will turn into the Orange-tip butterfly (6), which has a broad orange patch on the tip of its front wings. This butterfly is very gay when it is flying, but when it settles (8) and folds its wings upwards, it can scarcely be seen on the flowers of the wild parsley from which it sips honey. This is because the underside of the wings are dotted with green and like the tiny parsley flowers with their white petals and green centres.
Another common butterfly is the small Heath (9) which may be seen any fine day in June or September sipping honey from the heath on the common. It feeds as a green caterpillar on the tall grasses, and comes out a pretty little butterfly with tawny yellow wings, with a round eye-spot.
Now you know how to look for caterpillars, and chrysalises, and butterflies, you can learn about them for yourself. Anywhere on the violet beds you may find the spiny caterpillars of the pretty striped and dotted butterflies called Fritillaries. Blue butterflies are found mostly in chalk districts, though the Common Blue lives almost everywhere, and you may often see the little Copper butterflies flying with it, their dark glittering wings gleaming amongst the lovely blues. And wherever you see a butterfly on the wing you should try to follow it till it alights, for one of the most interesting points to notice, among all butterflies, is how the under colour of their wings helps to hide them when they are resting, while the upper colour is bright and gay.
Bring in caterpillars and chrysalises, and watch them. Notice the plant on which the caterpillar feeds. Compare the under surface of their wings with the plants on which they settle.