2. And in some diseases lice are very common. There is a kind of lice, which they call wild, and are harder than the common sort, which are difficult to eradicate from the body. The heads of children are most subject to be infested with lice, and men the least so, for women are more liable to them than men. Those that have lice in the head are less subject to headache. Many other animals are infested with lice: for both birds have them, and those which are called phasiani, unless they dust themselves, are destroyed by them. And so are all those creatures which have feathers with a hollow stem, and those which have hair, except the ass, which has neither lice nor ticks. Oxen have both; sheep and goats have ticks, but no lice; hogs are infested with large, hard lice, and dogs with those which are called cynoraïstæ. All lice originate in the animals that are infested with them. All creatures that have lice, and wash themselves, are more liable to them when they change the water in which they bathe. 3. In the sea is a kind of lice[182] growing on fish; but these do not originate in the fish, but in the mud. Their appearance is that of wood-lice with many feet, except that they have a wide tail. There is one species of marine lice which occur everywhere, and especially infest the trigla. All these creatures are furnished with many legs, are exsanguineous, and insects. The œstrus[183] of the thynnus occurs near the fins: in shape it is like a scorpion, and as large as a spider. In the sea between Cyrene and Egypt, there is a fish called the phtheira, which accompanies the dolphin; it is the fattest of all fish, because it enjoys an abundance of the food which the dolphin hunts for. [182] Perhaps Oniscus Ceti, or Isora. [183] Perhaps Lernœa branchialis. 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. [184] Tinea pellionella, or T. sarcitella. [185] Dumestes Pellio, and D. lardarius. [186] Phalangium cancroides.