Among the handsomest of all northern butterflies is the purple emperor, which you may sometimes see flying round the tops of the tallest trees in large woods in the south of England. Far commoner, however, are the large, small, and green-veined whites, whose caterpillars are so destructive to cabbages; the scarlet admiral, with broad streaks of vermilion across its glossy black wings; the peacock, with its four eye-like blue spots on a russet ground; the tortoise-shells, mottled with yellow and brown and black; and the pretty little blues, which one may see in almost every meadow from the middle of May till the end of September. Then there are the brimstone, with its pale yellow wings, which with the blues dance along the roadways in little whirling companies all summer; the meadow-brown and the large heath, to be seen in thousands in every hayfield; the small heath and the small copper, even more plentiful still; the fritillaries, some of which live in woods, and some on downs, and some in marshy meadows; the pretty orange-tip, with pure white wings tipped with yellow; and the odd little skippers, which flit merrily about grassy banks in the warm sunshine in May and again in August--besides several others, which are so scarce or so local that hardly anybody ever sees them. MOTHS You can easily tell moths from butterflies by looking at their antennæ, or feelers, which have no knobs at the tips, as those of butterflies have. Their number also is very great, and we can mention only a few of the most remarkable. First among these is the splendid death's-head sphinx, or hawk, the largest of all the insects, which sometimes measures five inches from tip to tip of its wings when they are fully spread. It owes its name to the curious patch of light-brown hairs on its thorax, which looks just like a skull. The caterpillar is a huge yellowish creature, often nearly six inches long, with a blue horn at the end of its body, and seven blue stripes, edged with white, on either side. It lives in potato-fields, hiding underground by day and coming out at night to feed upon the leaves. And it is an odd fact that both the caterpillar and the perfect insect have the power of squeaking rather loudly. The moth appears in October. The humming-bird hawk-moth flies by day, and you may often see it hovering over flowers in the garden, with its long trunk poked down into a blossom in order to suck up the sweet juices. As it does so it makes quite a loud humming noise with its wings, like the little bird from which it takes its name. And sometimes you may see a bee-hawk, which has transparent wings, hovering in front of rhododendron blossoms in just the same way.