A single Cicadella is usually crouching invisible in the depths of the foam; sometimes there are two or three or more. In such cases, it is a fortuitous association, the fabrics of the several workers being so close together that they merge into one common edifice. Let us see the work begin and, with the aid of a magnifying-glass, follow the creature’s proceedings. With her sucker inserted up to the hilt and her six short legs firmly fixed, the Cicadella remains motionless, flat on her stomach on the long-suffering leaf. You expect to see froth issuing from the edge of the well, effervescing under the action of the insect’s implement, whose lancets, ascending and descending in turns and rubbing against each other like those of the Cicada, ought to make the sap foam as it is forced out. The froth, so it would seem, must come ready-made from the puncture. That is what the current descriptions of the Cicadella tell us; that was how I myself pictured it on the authority of the writers. All this is a huge mistake: the real thing is much more ingenious. It is a very clear liquid that comes up from the well, with no more trace of foam than in a dew-drop. Even so the Cicada, who possesses similar tools, makes the spot at which she slakes her thirst give forth a limpid fluid, with not a vestige of froth to it. Therefore, notwithstanding its dexterity in sucking up liquids, the Cicadella’s mouth-apparatus has nothing to do with the manufacture of the foamy mattress. It supplies the raw material; another implement works it up. What implement? Have patience and we shall see. The clear liquid rises imperceptibly and glides under the insect, which at last is half inundated. The work begins again without delay. To make white of egg into a froth we have two methods: we can whip it, thus dividing the sticky fluid into thin flakes and causing it to take in air in a network of cells; or we can blow into it and so inject air-bubbles right into the mass. Of these two methods, the Cicadella employs the second, which is less violent and more elegant. She blows her froth. But how is the blowing done? The insect seems incapable of it, being devoid of any air-mechanism similar to that of the lungs. To breathe with tracheæ and to blow like a bellows are incompatible actions. Agreed; but be sure that, if the insect needs a blast of air for its manufactures, the blowing-machine will be there, most ingeniously contrived. This machine the Cicadella possesses at the tip of her abdomen, at the end of the intestine. Here, split lengthwise in the shape of a Y, a little pocket opens and shuts in turns, a pocket whose two lips close hermetically when joined.