Very well. Life is arrested half-way through its work; the insect does not attain the ultimate form of which it bears the emblem. For all its scientific turn of phrase, the reply is not really a reply at all. The question returns under another guise: what causes that arrested development? The larva is born with the hope of flying at maturity. As a pledge of that fair future, it carries on its back four sheaths in which the precious germs lie slumbering. Everything is arranged according to the rules of normal evolution. Thereupon, suddenly, the organism does not fulfil its promises; it is false to its engagements; it leaves the adult insect without sails, leaves it with only useless rags. Are we to lay this nudity to the charge of the harsh conditions of Alpine life? Not at all, for the other hoppers, living on the same grassy slopes, manage very well to achieve the wings foretold by the larva’s rudiments. Men tell us that, from one attempt to another, from progress to progress, under the stimulus of necessity, animals end by acquiring this or that organ. No other creative intervention is accepted than that of need. This, for instance, is the way in which the Locusts went to work, in particular those whom I see fluttering over the ridges of the Ventoux. From their niggardly larval flaps they are supposed to have extracted wings and wing-cases, by virtue of secret and mysterious labours rendered fruitful by the centuries. Very well, O my illustrious masters! And now tell me, if you please, what reasons persuaded the Pedestrian Locust not to go beyond his rude outline of a flying-apparatus. He also, surely, must have felt the prick of necessity for ages and ages; during his laborious tumbles amid the broken stones, he must have felt the advantage that it would be for him to be relieved of his weight by means of wing-power; and all the endeavours of his organism, striving to achieve a better lot, have not yet succeeded in spreading bladewise his incipient wings. If we accept your theories, under the same conditions of urgent necessity, diet, climate and habits, some are successful and manage to fly, others fail and remain clumsy pedestrians. Short of resting satisfied with words and passing off chalk for cheese, I abandon the explanations offered. Sheer ignorance is far preferable, for it prejudges nothing. But let us leave this backward one who is a stage behind his kinsmen, no one knows why. Anatomy has its throwbacks, its halts, its sudden leaps, all of which defy our curiosity. In the presence of the unfathomable problem of origins, the best thing is to bow in all humility and pass on. CHAPTER XVIII THE LOCUSTS: THEIR EGGS