For two reasons the experiment does not satisfy me. First of all, to give gauze to be pierced by insects with tools made to pierce lumps as hard as tufa does not seem a happy idea; you cannot expect a navvy’s pickaxe to do the same work as the scissors of a seamstress. Secondly, the transparent glass prison seems ill chosen. As soon as it had opened a way through the thickness of its earthen dome, the insect found itself in daylight, and to it daylight means final deliverance and freedom. It strikes against an invisible obstacle—the glass, and glass does not suggest an obstacle to it. Beyond, it sees a free space bathed in sunshine. It exhausts itself in efforts to fly there, unable to comprehend the uselessness of struggling against this strange, invisible barrier, and perishes, obstinate and exhausted, without a glance at the gauze which closes the conical tube. The experiment must be repeated under better conditions. The obstacle I selected was common gray paper—opaque enough to keep the insect in the dark—thin enough not to offer serious resistance to the prisoner’s efforts. As there is a vast difference by way of obstacle between a paper partition and a vault of unbaked clay, let us see first if Chalicodoma muraria knows how, or rather if it is able, to pierce such a barrier. The two mandibles—pickaxes adapted to pierce hard mortar—are they also scissors capable of cutting thin material? That is the point to be ascertained. In February, when the insect is already in the perfect state, I withdrew a certain number of cocoons uninjured from their cells, and placed each separately in a piece of reed, closed at one end naturally, open at the other. The pieces of reed represented the nest-cells. The cocoons were introduced so that the head of the insect should turn to the opening. Finally, my artificial cells were closed in various ways. Some had a stopper of kneaded earth, which, when dry, answered in thickness and consistency to the mortar of the nest; others were shut by a cylinder of Sorghum vulgare at least a centimetre thick, and others with a stopper of gray paper, solidly fixed by its edges. All these bits of cane were arranged side by side, vertically, in a box, with the artificial roof at the top, so that the insects were in the exact position they had in a nest. To open them they must do as they would had I not intervened—break through the wall overhead. I protected all with a large bell glass, and awaited the month of May when they would emerge.