But, however this may be, the evidence now offered us in favour of Darwin’s views can never be strengthened except in this way, so that, as far as proof is possible in such a matter, sexual selection as a law and principal agent of beauty in nature is now proved, though, at the same time, several more facts are added to those upon which the counter hypothesis seems based, and which would certainly prove it in Topsy-turvydom. To take these first, the authors of the paper in question have sought to apply to spiders “the hypothesis that the brighter colour of the male is due to his greater activity and vital force.” “Beginning,” they say, “with the most brilliant family—the _Attidæ_—we find that the females are, with few exceptions, larger, stronger, and more pugnacious than the males. Thus we placed two females of _Phidippus morsitans_ together in a glass jar. No sooner did they observe each other than both prepared for battle. Eyeing each other with a firm glance, they slowly advanced, and in a moment were locked in deadly combat. Within a few seconds the cephalothorax of one was pierced by the fang of the other, and with a convulsive tremor it relaxed its hold and fell dead. We placed together eight pairs in all, and in each instance the fight was short and even to the death. Subsequently we put in a well-developed male, which, though smaller, was compactly built and apparently strong enough to bring the virago to terms, but to our surprise he seemed alarmed and retreated, trying to avoid her. She, however, followed him up and finally killed him.”[132] So much for _Phidippus morsitans_. Coming to _Dendryphantes elegans_, the authors, who kept a number together in a large box, “were much struck by the greater quarrelsomeness of the females. They would frequently go out of their way to chase each other, and they were much more circumspect in approaching each other than were the males.”[133] Again they say, “Valkenaer, Menge, Hentz, and others give numerous instances where the male meets his death through the fierceness of his mate. In fact the danger is so imminent that after a successful courtship it is the habit in several genera (e.g. _Epeira_ and _Tegnaria_) for the male to retire with precipitation from the web of the female as a reasonable precaution; yet the rule is for the male to be more ‘beautified’ than the female.”[133]