The caterpillar, too, varies almost as much in colour as the moth. Sometimes it is reddish-brown; sometimes it is greenish-brown; sometimes it is yellowish-brown. But it always looks very much like a piece of stick; and it always has eight raised reddish spots on its back, which look just like buds before they begin to burst into leaf. You may find it in August, feeding on the leaves of lime, birch, and oak trees. In September it buries itself in the ground, and changes to a rather fat brown chrysalis, out of which the moth appears in the following May. [Illustration: PLATE XXXVI 1. Willow Beauty 2. Large Emerald] PLATE XXXVI THE WILLOW BEAUTY (1) I am sorry to say that I cannot tell you why this moth is called the “Willow Beauty.” For, in the first place, it is not a very beautiful insect. Both its front and hinder wings are greyish-brown all over, with a few wavy black lines running across them, and one pale zigzag streak near the outer margin. Certainly, one would hardly call it a “beauty.” And then, in the second place, it has nothing to do with willow trees; for its grey, twig-like caterpillar feeds on the leaves of rose-bushes, and plum trees, and pear trees, and birch trees, and sometimes on those of lilac and elder, but never on the leaves of willows. This moth is a very common one indeed in all parts of the country, and from the middle of June until the beginning of August you may see it in numbers, resting with outspread wings on fences and tree-trunks during the day, and fluttering round gas-lamps in the evening. There is another moth which is very like the “willow beauty,” but is nearly twice as big, and is rather lighter in colour. This is called the “great oak beauty,” and you may sometimes see it resting on the trunks of oak trees in June. PLATE XXXVI THE LARGE EMERALD (2) The “emeralds” are pale green moths with very delicate wings, and the Large Emerald is the finest and most beautiful of them all. It is almost as large as the “swallow-tail moth,” and when it first comes out of the chrysalis its wings are of the most lovely green colour, with three wavy white lines across the front pair, and a scalloped white line and a row of white dots across the hinder ones. But after two or three days it begins to fade; and if you were to put it away in a collection you would most likely find after a few months that it was nearly white. The Large Emerald is not a very common moth, but you may sometimes find it by shaking bushes and the branches of trees in June and July. The caterpillar feeds on the leaves of birch and elm, and is green in colour, with a yellow line along each side, and six pairs of little reddish bumps which look like tiny buds. About the end of May it forms a kind of cocoon by spinning together two or three leaves of its food-plant, and turns into a brownish-green chrysalis, with two rows of reddish spots on its back. [Illustration: PLATE XXXVII