It is still doubtful how far male insects of the true six-legged group appeal to the females by colour-display, even when they are brightly coloured, or in other ways than by perfumes (which they do very generally), but among the spiders there are some kinds (not common ones) in which the males have on the front of the body one or two extraordinarily brilliant spots of colour (red, apple-green, or yellow). The male moves round the female in courtship, and poses himself in most curious attitudes, so as to exhibit the brilliant colour to her; forcing it, as it were, on her attention. In other species of spiders the male dances and circles round the female, making curious and definite antics. Some spiders also have rasp-like organs, with which they can make a kind of singing note, which appears to fascinate the other sex. The vibration of a tuning-fork will cause some spiders to dance! In most spiders the female is much larger than the male--in some cases, ten times as large--and the approach of the male to the female is a dangerous business for him, for usually after his embrace she turns on him, kills him, and eats him. This is almost a unique case amongst animals (though ancient legends tell of princesses of similar ferocity), and curiously enough is not invariable among all species of spider. In some the males and females are quite friendly. The ogre-like habit of female spiders is not so injurious a thing as it may appear. For the most nourishing food is thus afforded to the female who has to ripen her eggs, and take care of her young, whilst, if the male escapes, it appears that he is short-lived and very soon dies. This cannibal tendency is very strongly developed also in the allied group, the scorpions. Two hundred scorpions were left in a cage in the South of France, whilst the naturalist (Maupertuis) who had placed them there was obliged to go to Paris. On his return he found one large, very plump and active scorpion in the box, surrounded by legs and hard bits of the bodies of the rest. The survivor was in the position of Gilbert's ancient mariner, who said that he was "the cook and the mate, and the captain's boy and the crew of the _Nancy Bell_." Scorpions do not perform any courtship display. The males and females are of equal size, and dance together, holding one another by their large claws, before mating and retiring into a burrow.