I wish now to put this question: What relation that we can see or imagine to the passion of love and the business of courtship, have these dancing and vocal performances in nine cases out of ten? In such cases, for instance, as that of the scissors-tail tyrant-bird, and its pyrotechnic evening displays, when a number of couples leave their nests containing eggs and young to join in a wild aerial dance: the mad exhibitions of ypecahas and ibises, and the jacanas' beautiful exhibition of grouped wings: the triplet dances of the spur-winged lapwing, to perform which two birds already mated are compelled to call in a third bird to complete the set: the harmonious duets of the oven-birds, and the duets and choruses of nearly all the wood-hewers, and the wing-slapping aerial displays of the whistling widgeons--will it be seriously contended that the female of this species makes choice of the male able to administer the most vigorous and artistic slaps? The believer in the theory would put all these cases lightly aside, to cite that of the male cow-bird practising antics before the female and drawing a wide circle of melody round her; or that of the jet-black, automaton-like, dancing tyrant-bird; and concerning this species he would probably say that the plain-plumaged female went about unseen, critically watching the dancing of different males, to discover the most excellent performer according to the traditional standard. And this was, in substance, what Darwin did. There are many species in which the male, singly or with others, practises antics or sings during the love-season before the female; and when all such cases, or rather those that are most striking and bizarre, are brought together, and when it is gratuitously asserted that the females _do_ choose the males that show off in the best manner or that sing best, a case for sexual selection seems to be made out. How unfair the argument is, based on these carefully selected cases gathered from all regions of the globe, and often not properly reported, is seen when we turn from the book to nature and closely consider the habits and actions of all the species inhabiting any _one_ district. We see then that such cases as those described and made so much of in the _Descent of Man,_ and cases like those mentioned in this chapter, are not essentially different in character, but are manifestations of one instinct, which appears to be almost universal among the animals. The explanation I have to offer lies very much on the surface and is very simple indeed, and, like that of Dr. Wallace with regard [Footnote: It is curious to find that Dr. Wallace's idea about colour has been independently hit upon by Ruskin. Of stones he writes in _Frondes Agrestis_:--"I have often had occasion to allude to the apparent connection of brilliancy of colour with vigour of life and purity of substance. This is pre-eminently the case in the mineral kingdom. The perfection with which the particles of any