17. When they have stung anything they perish, for they cannot withdraw their sting from the wound without tearing their own entrails; but they are frequently saved, if the person stung will take care to press the sting from the wound: but when its sting is lost, the bee must perish. They will kill even large animals with their stings, and a horse has been known to perish, if attacked by bees. The rulers are the least cruel and stinging. 18. If any bees die in the hive, they carry them out; and in other respects the bee is a very clean creature. For this reason they also eject their excrement when in flight, for the smell is bad. It has been already observed that they dislike bad smells and the scent of unguents, and that they sting persons who use such things. They also die from other causes, as when the rulers in the hive are in great numbers, and each leads out a portion of the swarm. The toad also destroys bees, for it blows into the entrance of the hive, and watches for and destroys them as they fly out. The bees cannot inflict any injury upon it, but their keepers destroy it. 19. Some bee-keepers say that the kind of bee which makes an inferior and rough comb is the young of the others, and that it is the result of imperfect skill. They are young when a year old; young bees do not sting so severely as old bees; for this reason the swarms are carried to the apiaries, for they are those of young bees. When honey is short they eject the drones, and put figs and other sweet things near them. The elder bees work in the hives, and become hairy from remaining within. The younger ones go out in the fields, and are smoother: and they kill the drones when they have no longer any room for them, for they are placed in a recess of the hive. When a swarm has been weak, strange bees have been known to come and fight with them, and take away their honey; and when the bee-keeper killed them the others came out and defended themselves, and would not injure the man. 20. Other diseases, and especially one called clerus, frequently attack strong swarms. In this disease small worms are produced on the floor of the hive, and as these increase, the whole swarm is held, as it were, in a spider's web, and the combs decay. There is another disease, which is like a wildness in the bees, and causes a strong smell in the hives. The bees should be fed on thyme, the white sort is better than the red. In close weather they should have a cool place, and a warm one in the winter. They suffer the most when they work with materials affected with the rust.