Would you like to know why it is that flies stick to the web as soon as they touch it? The microscope shows us. All the way along, the spiral thread is set with very tiny drops of liquid gum. So tiny are these drops indeed, that there are between eighty and ninety thousand of them in a large web! And would you like to know why it is that the spider does not stick to the web as the flies do? Well, the fact is that only the spiral thread is set with these little gummy drops, and that as the spider runs about over her web she is most careful to place her feet only on the straight threads, and never on the spiral line. Other spiders, however, snare their prey in quite a different way. THE MARMIGNATTO This small spider, found on our western plains, is remarkable for feeding on large insects, such as grasshoppers and field-crickets, which it catches in an ingenious manner. It stretches a few silken threads across a narrow path way, quite close to the ground, along which these insects are likely to pass, and lies in wait just opposite until a grasshopper or a cricket approaches. When it comes to the threads the insect is sure to get at least one of its feet entangled. Then it stops, and tries to shake itself free. The only result of its struggles, of course, is that its other feet become entangled too; and while it is struggling the marmignatto springs upon its back, fastens a silken thread to it, springs down again, and fastens the other end to a grass-stem close by. Over and over again it does this, and before very long the unfortunate insect is firmly fastened down by hundreds of threads, and is quite unable to break free, or even to move one of its legs. Then the spider leaps upon its back once more, plunges its fangs into its body, and proceeds to suck its blood. HUNTING-SPIDERS Perhaps you may have seen little hairy black spiders, with white markings upon the upper part of their bodies, running about in an odd jerky way on sunny fences and walls. These are called hunting-spiders, because they hunt their prey instead of snaring it. You may see them gradually creeping up to a fly, so slowly that they hardly seem to move, and then suddenly leaping upon it when they are about two inches away. Then spider and fly, locked in one another's embrace, go falling toward the ground together. But they never reach it, for wherever a hunting-spider goes it always trails a rope of silk behind it, and fastens it down at intervals. So when it springs from the fence it is brought up at once by its own thread, and swings in the air till its victim is dead. Then it just climbs up its thread, and so gets back to the fence. BIRD-SPIDERS