But the laying takes a long time when it is all performed on the same support. Allowing ten minutes to a cell, the series of forty which I have sometimes seen represents a period of six to seven hours. The sun therefore can alter its position considerably before the Cicada has finished her work. In that case the rectilinear direction becomes bent into a spiral curve. The mother turns around her stalk as the sun itself turns; and her row of pricks suggests the course of the gnomon’s shadow on a cylindrical sundial. Very often, while the Cicada is absorbed in her work of motherhood, an infinitesimal Gnat, herself the bearer of a boring-tool, labours to exterminate the eggs as fast as they are placed. Réaumur knew her. In nearly every bit of stick that he examined he found her grub, which caused him to make a mistake at the beginning of his researches. But he did not see, he could not see the impudent ravager at work. It is a Chalcidid some four to five millimetres [23] in length, all black, with knotty antennæ, thickening a little towards their tips. The unsheathed boring-tool is planted in the under part of the abdomen, near the middle, and sticks out at right angles to the body, as in the case of the Leucospes, [24] the scourge of certain members of the Bee-tribe. Having neglected to capture the insect, I do not know what name the nomenclators have bestowed upon it, if indeed the dwarf that exterminates Cicadæ has been catalogued at all. What I do know something about is its calm temerity, its brazen audacity in the immediate presence of the colossus who could crush it by simply stepping on it. I have seen as many as three exploiting the unhappy mother at the same time. They keep close behind each other, either working their probes or awaiting the propitious moment. The Cicada has just stocked a cell and is climbing a little higher to bore the next. One of the brigands runs to the abandoned spot; and here, almost under the claws of the giantess, without the least fear, as though she were at home and accomplishing a meritorious act, she unsheathes her probe and inserts it into the column of eggs, not through the hole already made, which bristles with broken fibres, but through some lateral crevice. The tool works slowly, because of the resistance of the wood, which is almost intact. The Cicada has time to stock the next floor above. As soon as she has finished, a Gnat standing immediately behind her, waiting to perform her task, takes her place and comes and introduces her own exterminating germ. By the time that the mother has exhausted her ovaries and flies away, most of her cells have, in this fashion, received the alien egg which will be the ruin of their contents. A small, quick-hatching grub, one only to each chamber, generously fed on a round dozen raw eggs, will take the place of the Cicada’s family.