My satisfaction would be equally great if I knew why the Iris-weevil’s [84] tarsus has a single nail, whereas the other insects have two, set side by side and bent into a hook. Why was one of these two little claws suppressed? Would it not have been useful to the insect? One would think so. The little Weevil thus mutilated is a climber; she clambers up the smooth stems of the iris; she explores the flowers, visiting the lower surface of the petals as well as the upper; she walks upside down on the slippery pods. An extra hook would do much to ensure her steadiness; yet the thoughtless Weevil deprives herself of it, though by law she has a right to the double claw invariably wielded by the others, even in her own long-nosed clan. What then is the secret of the little Iris-weevil’s missing finger-nail? A tiny claw the less, though a serious business where matters of principle are concerned, is after all a detail of no great material value; one needs a lens to perceive the irregularity. But here is something that the eye can see without the aid of the magnifying-glass. A Locust from the green slopes of the Alps, Pezzotettyx pedestris, [85] who dwells on the higher ridges of Mont Ventoux, [86] renounces her right to wings of any kind; she reaches the adult stage while preserving the larval formation. The approach of the wedding-day makes her a little handsomer, adds a touch of coral-red to her sturdy thighs and of sky-blue to her shanks; but there all progress stops. She becomes ripe for marriage and maternity without acquiring the power of flying which the other Acridians possess in addition to that of leaping. Among the hoppers, all endowed with wings and wing-cases, she remains a clumsy pedestrian, as her Latin affix, pedestris, informs us. Nevertheless, the cripple bears on her shoulders a pair of skimpy sheaths which contain the organs of flight, incapable of unfolding. By what curious evolutionary whim is the pretty Locust with the azure legs deprived of the wings and wing-cases of which she carries the germs in two miserable little bundles? She is promised the gift of flight and does not receive it. For no appreciable reason, the wheels of the animal mechanism are arrested. Stranger still is the case of the Psyches, whose females, unable to become the Moths promised in their early stages, remain caterpillars, or rather change into wallets stuffed with eggs. Wings with gorgeous scales, the supreme prerogative of Moth and Butterfly, are denied them. The males alone achieve the promised shape; they turn into plumed dandies, clad in black velvet, and are excellent flyers. Why does one—and that one the more important—of the sexes remain a wretched little sausage, while the other is made glorious by the metamorphosis?