A pair that continue to exist as such, a couple that join forces and unite their industry for their offspring’s welfare, certainly represent enormous progress, perhaps the greatest in the animal kingdom. One day, in the midst of the isolated existences, the household appeared, the invention of an inspired Dung-beetle. How is it that his magnificent acquirement is the property of a few, instead of extending all around, from one species to another, throughout the guild? Can it be that Scarabæi and Copres would have nothing to gain, in saving of time and labour, if the mother, instead of working alone, had an assistant? Things would move faster, so it seems to me, and a more numerous family would be permissible, a possibility not to be despised when one has an eye to the prosperity of the species. How, on his side, did the Geotrupes think of combining the two sexes in building the nest and stocking the larder? The abrupt transformation of the usual airy paternity of the insect into something that rivals motherhood in tenderness is so serious and so rare an event that we long to discover the cause of it, if indeed we may hope to do so with the sorry means of information at our disposal. One idea occurs to us at once: may there not be some connection between the male’s superior size and his liking for hard work? Endowed with greater robustness and vigour than the mother, he who is usually so lazy has become a zealous helper; the love of work has come from a surplus of unspent strength. Take care: this apparent explanation will not hold water. The two sexes of the Mimic Geotrupes scarcely differ in size; the advantage is often even in the female’s favour; and nevertheless the male lends assistance to his companion: he is as eager a well-sinker, as energetic a presser as his big stercoraceous kinsman. And here is a still more conclusive argument: among the Anthidia, [53] those Bees who weave cotton-stuffs or knead resin, the male, though much larger than the female, is an absolute idler. He, so strong, so stout of limb, take part in the work! Never! Let the mother, the feeble mother, wear herself out while he, powerful fellow that he is, frolics among the speedwell and the lavender. It is not physical strength, therefore, that has made the Geotrupian paterfamilias into a worker devoted to his children’s welfare. And this is as much as our investigations tell us. To pursue the problem would be a vain endeavour. The origin of faculties escapes us. Why is this gift bestowed here and that gift there? Who knows? Can we indeed ever hope to know? One point alone stands out clearly: instinct is not dependent on structure.