So, too, Agriopas informs us that Demænetus, the Parrhasian, during a sacrifice of human victims, which the Arcadians were offering up to the Lycæan Jupiter, tasted the entrails of a boy who had been slaughtered; upon which he was turned into a wolf, but, ten years afterwards, was restored to his original shape and his calling of an athlete, and returned victorious in the pugilistic contests at the Olympic games. [Illustration: VIPER, OR ADDER.—_Pelias Berus._] With reference to serpents, it is generally known, that they assume the color of the soil in which they conceal themselves. The different species of them are innumerable. The cerastes has little horns, often four in number, projecting from the body, by the movement of which it attracts birds, while the rest of its body lies concealed. The amphisbæna has two heads, that is to say, it has a second one at the tail, as though one mouth were too little for the discharge of all its venom. Some serpents have scales, some a mottled skin, and they are all possessed of a deadly poison. The jaculus[97] darts from the branches of trees; and it is not only to our feet that the serpent is formidable, for he even flies through the air just as though he were hurled from an engine. The neck of the asp puffs out, and there is no remedy whatever against its sting, except the instant excision of the affected part. This reptile, which is so deadly, is possessed of this one sense, or rather affection; the male and the female are generally found together, and the one cannot live without the other; hence it is that, if one of them happens to be killed, the other takes incredible pains to avenge its death. It follows the slayer of its mate, and will single him out among never so large a number of people, by a sort of instinctive knowledge; with this object it overcomes all difficulties, travels any distance, and is only to be avoided by the intervention of rivers or an accelerated flight. It is really difficult to decide, whether Nature has altogether been more liberal of good or of evil. First of all, however, she has given to this pest but weak powers of sight, and has placed the eyes, not in the front of the head, so that it may see straight before it, but in the temples, so that it is more frequently put in motion by the approach of the footstep than through the sight. The ichneumon, however, is its enemy to the very death.