One of the handsomest of European insects is the musk-beetle, which you may often find sunning itself on the trunks and leaves of willow-trees in England in July. Often you can smell it long before you find it, for it gives out a strong odor much like that of musk. This beetle is sometimes nearly an inch and a half long, with long legs and still longer waving black feelers. In color it is rich golden green with a tinge of copper. But if you put one of its wing-cases under the microscope, it looks like a piece of green velvet studded all over with diamonds, and rubies, and sapphires, and emeralds, and topazes, which seem to turn into one another with every change of light. The grub of this beetle lives inside the trunks of dying willow-trees, and feeds upon the solid wood. Then there are the turnip-fleas, little black beetles with a yellow stripe on each wing-case, which skip about just as fleas do, by means of their hind legs. They are only too common in turnip-fields, and often do most serious mischief, nibbling off the seed-leaves of the young plants as soon as they push their way above the surface of the ground, and so destroying the greater part or even the whole of the crop. And, lastly, there are the ladybirds, common everywhere. But perhaps you did not know that they are among the most useful of insects. The fact is that both as grubs and as perfect insects they live upon the green blight, or greenfly, an aphis which is terribly mischievous in fields and gardens, and destroy it in thousands of thousands. Indeed, if it were not for ladybirds, and for one or two other insects which help them in their task, we should find it quite impossible to grow certain crops at all. [Illustration: INSECTS INJURIOUS TO AMERICAN MAPLE TREES. BORING BEETLE (Plagionotus): 1, place where egg was laid; 2, borer or grub in September from egg laid same season; 3, nearly fully grown borer; 4, adult beetle (black and yellow); 5, hole through which beetle escaped from its chrysalis in the burrow; 6, dust of borings packed in a burrow. MAPLE-TREE PRUNER (Elaphidium): 7, 7a, grubs or borers in burrows; 8, pupa; 9, beetle (brown). COTTONY SCALE (Pulvinaria): 10, active young (pink); 11, adult female scales, each concealing many eggs under the woolly mass; 12, leaf with young scale-insects on its under side.] EUPLEXOPTERA Next after the beetles comes the order of the _Euplexoptera_, which means beautifully folded wings. This order contains the earwigs. We do not know much about these insects in the United States; but they are so constantly spoken of in books about England, where they are numerous, that it will be well to describe them.