Chapter XXVI.

1. There are also other minute animals, as I observed before, some of which occur in wool,[184] and in woollen goods; as the moths, which are produced in the greatest abundance when the wool is dusty, and especially if a spider is enclosed with them, for this creature is thirsty, and dries up any fluid which may be present. This worm also occurs in garments. There is one which occurs in old honeycombs, like the creature which inhabits dry wood: this appears to be the least of all creatures, it is called acari, it is white and small. Others also are found in books,[185] some of which are like those which occur in garments: others are like scorpions;[186] they have no tails, and are very small. And on the whole, they occur in everything, so to say, which from being dry, becomes moist, or being moist, becomes dry, if it has any life in it.

2. There is a little worm which is called xylophthorus,[187] which is no less extraordinary than these animals; for its variegated head is projected beyond its case, and its feet are at the extremity, as in other worms. The rest of the body is contained in a case made of a substance like spider's web, and a dry material on the outside of this; so that it appears to walk about with this attached to it. These creatures are attached to their case, and as a snail to its shell, so the whole of the case is joined to the worm, and it does not fall out of it, but is drawn out of it, as if they were joined together. If a person pulls off the case, the creature dies, and becomes as helpless as a snail without its shell. As time advances, this grub becomes a chrysalis, like a caterpillar, and lies without motion: but the nature of the winged creature that is produced has never been ascertained.

3. The wild figs upon the fig-trees contain a creature called psen;[188] this is at first a little worm, and afterwards having ruptured the case, the psen flies out, and leaves it behind. It then pierces the unripe figs, and causes them not to fall off, wherefore gardeners place wild fruit near the cultivated kinds, and plant the wild and cultivated plants near each other.