This door is a marvel; the outside is generally covered with earth similar in color to the ground by which it is surrounded, thus rendering it difficult to find the burrow. Trap-door spiders are found in many parts of the world. But many species of spiders live in burrows that have no doors. Some of these burrow spiders go out at night as well as in the daytime, but they hardly ever move far from their burrows. I have often seen them watching from the entrance of their caves for prey. How queer they look! They must have a wonderful sense of hearing, for at the least noise they run back inside of their burrows. They seem to know when the noise does not come from an enemy, but from some insect upon which they intend to prey. One day one of these burrow spiders was watching for its food, when suddenly it pounced upon a big caterpillar which had made its appearance, and, after a desperate struggle, the poor caterpillar was carried into the burrow, though still alive. After half an hour I carefully demolished the burrow, and found the spider at the bottom; the caterpillar was partly devoured, and I saw the remains of legs, wings, and heads of insects which had been captured and eaten up. I took the spider out; it seemed stupefied, and walked to and fro as if it did not know where to go. When once a spider has built its burrow it dwells in it for a long time. These burrows are built in such a manner that when it rains the water can not get in. Have you ever thought, when looking at the web of a spider, what an admirable piece of work it is, and how this thread is manufactured? No lace is more beautifully worked. The thread is formed by a semi-liquid secretion, which comes out, at the will of the spider, through minute apertures, and which hardens into a thread by contact with the atmosphere. How strange that is! Spiders must have a great amount of knowledge, and are, no doubt, good barometers, for when a storm is impending they never will build or mend a web. There is a good reason for their not being extravagant in the use of their silk, for, although they can use at their will the secretion from which the thread is made, it requires time to reproduce it; so when you see a spider spinning new webs, it is a sign of fine weather coming. If you look closely at the web of a spider, you will surely be surprised at their wonderful skill. First a net-work of strong threads is built; these are the main beams, and between them the net made of smaller thread is spun. These webs are exceedingly elastic, for they have to resist the power of the wind. When the web has been long built, and has become stretched, they will sometimes go and fetch a little piece of wood, which they hang by a thread, and haul it to a spot where they think it will steady their structure.