The spiders are best known and hated as animals that bite. The biting apparatus is shown in Fig. 14, which represents the head and mandibles of _Epeira vulgaris_, seen from in front. When not in use, the claw is closed up against the mandible between the rows of teeth; but, when the jaws are opened to bite, the claws are turned outward, so that their points can be stuck into any thing between the jaws. Fig. 15 is the claw still more enlarged, showing a little hole near the point at _a_, out of which is discharged the secretion of a gland in the head, Fig. 5, _n_. The ordinary use of the mandibles is for killing and crushing insects, so that the soft parts can be eaten by the spider; and in this they are aided by the maxillæ, Fig. 1, E. They will sometimes chew an insect for hours, until it becomes a round lump of skin, with all the blood sucked out of it; this is then thrown away, the spider swallowing only such bits as may happen to be sucked in with the liquid portion. [Illustration: Fig. 14.] [Illustration: Fig. 15.] If let alone, no spiders bite any thing except insects useful for food; but, when attacked and cornered, all species open their jaws, and bite if they can; their ability to do so depending on their size, and the strength of their jaws. Notwithstanding the number of stings and pimples that are laid to spiders, undoubted cases of their biting the human skin are very rare; and the stories of death, insanity, and lameness from spider-bites, are probably all untrue. Many experiments have been tried to test the effect of the bites of spiders on animals. Doleschall shut up small birds with _Mygale Javanica_ and _Mygale Sumatrensis_, both large and strong spiders; and the birds died in a few seconds after being bitten. One of the spiders was left for ten days without food, and then made to bite another bird, which was injured, but in six hours recovered. The same author was bitten in the finger by a jumping spider. The pain was severe for a few minutes, and was followed by lameness of the finger, and gradually of the hand and arm, which soon went away entirely. Bertkau allowed spiders to bite his hand. On the ends of the fingers the skin was too thick; but between the fingers they easily pricked it. The bite swelled and smarted for a quarter of an hour, and then itched for some time, and for a day after itched whenever rubbed, as mosquito-bites will. He also experimented on flies, which died in a few minutes after being bitten. Mr. Blackwall, to test the poison of spiders, made several large ones bite his hand and arm, and at the same time pricked himself with a needle. Although the spiders bit deep enough to draw blood, the effect of their bite was exactly like that of the prick of the needle. No inflammation or pain followed, and both healed immediately.