No one, unless he be content with idle fancies, will admit that the cigar-roller can have tired of her cylinder one day and proceeded, as a crazy innovator, to make a hole in the casket of a fruit-stone. Such dissimilar industries do not suggest mutual connection. The first leaf-rollers, never knowing any lack of leaves, may perhaps have gone from one tree to others more or less like it; but to give up the art of leaf-rolling, so easy to acquire, and to become, when nothing compelled them to, strenuous nibblers of hard wood: that would have been idiotic. No acceptable reason would explain the desertion of the original trade. Such follies are unknown in the insect world. The exploiter of the sloe refuses in her turn to acknowledge herself as inspiring the cigar-maker: ‘What, I!’ she says, ‘I, give up my little blue plum, so savoury in its tartness! I, a chaser of goblets, abandon my chisel and, in a moment of madness, become a folder of leaves! What do you take me for? My grub dotes on the floury kernel; confronted with any other fare, above all with the meagre, tasteless roll of my colleague of the poplar, it would let itself die of hunger. So long as sloes or kindred fruits have existed, my race, thriving upon them, has never committed the folly of forsaking them in favour of a leaf. So long as they exist, we shall remain faithful to them; and, if ever they fail us, we shall perish to the last grub.’ The lover of the apricot is no less positive. She, who is so easy to establish in soft pulp, has taken good care not to advise her children to undertake the laborious task of perforating a shell or rolling a leaf into a cigar. According to the locality and the abundance of the fruit, her boldest innovation has been to pass from the apricot to the plum, the peach, or even the cherry. But how are we to admit that these lovers of fruit-pulp, well satisfied with their rich living, which has always been possible, in the old days and to-day alike, can ever have risked leaving the soft for the hard, the juicy for the dry, the easy for the difficult? None of these four is the head of the line. Is the common ancestor then an unknown species, dumped down, perhaps, in the schist-foliations whose venerable archives we began by consulting? Even if he were there, we should be none the wiser. The library of the stones preserves the forms but not the instincts; it says nothing of industries, because, let us repeat and again repeat, the insect’s tool tells us nothing of its trade. With the same rostrum the Weevil may follow very different callings. What the ancestor of the Rhynchites did we do not know and have no hope of ever knowing. The theorists, therefore, take their stand only on the vague and slippery ground of suppositions: ‘Let us admit,’ they say, ‘let us imagine that ... it might be that ...’ and so forth.