The North American termites do not build great clay hills or houses above ground, but some species make extensive galleries beneath the surface, while others hollow out a dead stump, or the dying branch of a tree, or even an old fence-post or telegraph pole, until it becomes a mere sponge, with a thin outside shell. NEUROPTERA The _Neuroptera_, or nerve-winged insects, form an order whose wings are divided up by horny nerves, or nervures, into such numbers of tiny cells, that they look as if they were made of the most delicate lace. The caddis-flies belong to this order--brownish insects with long thread-like feelers and broad wings, which are folded tentwise over the body when they are not being used. They are very common near ponds and streams, in which they pass the earlier part of their lives, living down at the bottom in most curious cases, which cover them entirely up with the exception of their heads. These cases are made of all sorts of materials. Some caddis-grubs merely fasten two dead leaves together, face to face, and live between them. Others make a kind of tube out of grains of sand, or tiny stones, or little bits of cut reed, all neatly stuck together with a kind of glue which resists the action of water. But the oddest case of all is made of tiny living water-snails, and you may sometimes see fifteen or twenty little snails all trying to crawl in different directions, while the grub is unconcernedly pulling them along in another! The grubs never leave these cases, but drag them about with them wherever they go. And when they find that their odd little homes are becoming too small, they just cut off a little piece at the end and add a little piece on in front, rather larger in diameter. And so they always manage to keep their homes of exactly the proper size. Most likely, too, you have heard of the ant-lion fly, which is a rather large fly with a slender body and four long narrow wings, and is found in many parts of the south of Europe, as well as in America. But the interest lies in the grub, or "ant-lion" proper, which has a most singular way of catching its insect victims. It digs a funnel-shaped pit in the sand, about three inches in diameter and two inches deep, by means of its front legs and its head. Then it almost buries itself at the bottom, and lies in wait to snap up any ants or other small insects which may be unfortunate enough to fall in. And if by any chance they should escape its terrible jaws and try to clamber up the sides, it jerks up a quantity of sand at them, and brings them rolling down again to the bottom, so that they may be seized a second time.