Can it not be in a similar fashion that the Cicada-grub bores its tunnel? Certainly the waste material flung up as it digs its way does not pass through its body; even if the soil were of the softest and most yielding character, earth plays no part whatever in the larva’s food. But, after all, cannot the materials removed be simply shot back as the work proceeds? The Cicada remains four years in the ground. This long life is not, of course, spent at the bottom of the well which we have described: this is just a place where the larva prepares for its emergence. It comes from elsewhere, doubtless from some distance. It is a vagabond, going from one root to another and driving its sucker into each. When it moves, either to escape from the upper layers, which are too cold in winter, or to settle down at a better drinking-bar, it clears a road by flinging behind it the materials broken up by its pickaxes. This is undoubtedly the method. As with the larvæ of the Capricorn and the Buprestes, the traveller needs around him only the small amount of free room which his movements require. Damp, soft, easily compressed earth is to this larva what the digested pap is to the others. Such earth is heaped up without difficulty; it condenses and leaves a vacant space. The difficulty is one of a different kind with the exit-well bored in a very dry soil, which offers a marked resistance to compression so long as it retains its aridity. That the larva, when beginning to dig its passage, flung back part of the excavated materials into an earlier gallery which has now disappeared is fairly probable, though there is nothing in the condition of things to tell us so; but, if we consider the capacity of the well and the extreme difficulty of finding room for so great a volume of rubbish, our doubts return and we say to ourselves: “This rubbish demanded a large empty space, which itself was obtained by shifting other refuse no less difficult to house. The room required presupposes the existence of another space into which the earth extracted was shot.” And so we find ourselves in a vicious circle, for the mere subsidence of materials flung behind would not be enough to explain so great a void. The Cicada must have a special method of disposing of the superfluous earth. Let us try and surprise his secret. Examine a larva at the moment when it emerges from the ground. It is nearly always more or less soiled with mud, sometimes wet, sometimes dry. The digging-implements, the fore-feet, have the points of their pickaxes stuck in a globule of slime; its other legs are cased in mud; its back is spotted with clay. We are reminded of a scavenger who has been stirring up sewage. These stains are the more striking inasmuch as the creature comes out of exceedingly dry ground. We expected to see it covered with dust and we find it covered with mud.