And in his Philoctetes he uses the word in the genitive case plural, φαβῶν. "The œnas, then," says Aristotle, "is something larger than the pigeon, and it has a puce-coloured plumage; but the phaps is something between the pigeon and the œnas. And the species called phassa is about as large as the common cock, but of the colour of ashes; and the turtle-dove is less than all the other species, and is of a cinder-colour. And this last is only seen in the summer, and during the winter it keeps in its hole. Now, the phaps and the common pigeon are always to be seen, but the œnas is only visible in the autumn. And the species called the phassa is said to be longer lived than any of the others; for it lives thirty or forty years. And the cock birds never leave the hens to the day of their death, nor do the hens ever desert the cock: but when one dies the other remains solitary: and crows, and ravens, and jackdaws all do the same thing. And in every kind of the genus pigeon, both male and female sit on the eggs in turn; and when the chickens are hatched, the cock bird spits upon them to prevent their being fascinated. And the hen lays two eggs, the first of which produces a cock and the second a hen. And they lay at every season of the year; so that they lay ten or eleven times a-year; and in Egypt they lay twelve times; for the hen conceives again the very next day to that in which it lays." And further on, in the same book, Aristotle says that the kind called περιστερὰ differs from the πελειὰς, and the πελειὰς is the least of the two. And the πελειὰς is easily tamed; but the περιστερὰ is black, and small, and has red rough legs; on which account no one keeps them. But he mentions a peculiarity of the species called περιστερὰ, that they kiss one another when courting, and that if the males neglect this, the hens do not admit their embraces. However, old doves do not go through this formality; but omit the kisses and still succeed in their suit, but the younger ones always kiss before they proceed to action. And the hens, too, make love to one another, when there is no cock at hand, kissing one another beforehand. But still, as there are no real results, the eggs which they lay never produce chickens. The Dorians, however, consider the πελειὰς and the περιστερὰ as identical; and Sophron uses the two words as synonymous in his Female Actresses. But Callimachus, in his treatise on Birds, speaks of the pyrallis, the dove, the wood-pigeon, and the turtle-dove, as all different from one another.