Coleoptera are given to cavalage, of duration varying from ten hours to two days. The male cockchafer pursues the female with fervour, he is so ardent that he often mounts other males, deceived by the odour of rut floating in the air. He seizes the female and holds her clamped by his forelegs and genital hooks. The union continues a day and a night, finally the male, exhausted, falls over backward, and still hooked by the penial pincers, is dragged along on his back by the impassive female who moves on feeding, pulling him over the leaves until death detaches him; then she lays and dies in her turn. Butterflies are likewise very fervent, the males make veritable voyages in quest of females, as Fabre has proved. They often fly coupled, the stronger female easily carrying the male: it is a quite frequent sight in the country, these butterflies with four wings who roll, a little bewildered from flower to flower, drunken ships going where the sails bid them. With flies, feminism is brought frankly into the love mechanism. The females have the copulative apparatus; they force their oviduct, then a veritable prong, into the male's belly; it is the females who make the mastering gesture, the male merely grips this gimlet with the hooks which surround his genital fent. It is this same augur which the female uses to bore the wood, or earth or flesh where she deposits her eggs. The coupling is end to end, and one of the easiest to observe. Here are enough examples to show what is permanent in the mechanism of true copulation, and what is variable in its exterior modes. Given the two chief pieces of the apparatus, the sword and the scabbard, nature, as one might say, leaves it to the imagination of each specie to decide the best manner of using them; all ways seem good if they fecundate. Nature has still more remarkable methods, for the sexual inventions of humanity are nearly all anterior or exterior to man. There is not one whose model, even perfected, is not offered him by the animals, by the most humble of animals.