There—and there only—you will see, not the air-tight paste of the rest of the work, but a stringy plug, a disk of coarse velvet bristling with tiny fibres, a round piece of loosely-made felt through which the gaseous exchanges can be effected. A filter takes the place of the solid material. The mere appearance is enough to tell us the function of this part. If doubts occurred to our minds, here is something to dispel them: I cover the fibrous expanse with several coats of varnish; I deprive the filter of its porousness, without interfering with any other part. Now let us see what happens. When the time comes for the emergence, with the first autumn rains, let us break open the pills. They contain nothing but shrivelled corpses. An egg is killed if you varnish it: when placed under the sitting Hen it remains a lifeless pebble. The chicken has died in the germ. So perish the Sacred Beetle, the Copris and the rest when we varnish the circular disk of felt which acts as a ventilator. This method of the porous plug is recognized as being so efficacious that it is in general use among the pill-makers of the remotest regions. The Splendid Phanæus and Bolbites onitoides, both from Buenos Aires, [52] employ it as zealously as the Dung-beetles of Provence. One of the dwellers in the pampas uses another process, prescribed by the material which she manipulates. This is Phanæus Milon, a ceramic artist and meat-packer. With very fine clay she fashions a gourd in the middle of which she places a round meat-pie made from the sanies of a corpse. The grub for which these victuals are intended hatches in an upper story, separated from the larder by a clay partition. How will this grub breathe, first in its cell upstairs and then in the lower room, when it has perforated the floor and reached the cold pasty? The house is a piece of pottery, an earthenware jar whose wall sometimes measures a finger’s-breadth in thickness. Air cannot possibly pass through such a casing. The mother, who knew this, made arrangements accordingly. Along the gourd’s neck she contrived a narrow passage through which a flow of air is possible. Without resorting to obstruction by means of varnish or anything else, we see quite plainly that this minute tunnel is a ventilating-shaft.