She does worse. When the time of the nymphosis comes, the Halictus mother goes to the cells rifled by the parasite and closes them with an earthen plug as carefully as she does the rest. This final barricade, an excellent precaution when the box is occupied by an Halictus in course of metamorphosis, becomes a screaming absurdity when the Dipteron has passed that way. Instinct does not hesitate in the face of this incongruity: it seals up emptiness. I say, emptiness, because the crafty maggot hastens to decamp the instant that the victuals are consumed, as though it foresaw an insuperable obstacle for the coming Fly: it quits the cell before the Hymenopteron closes it. To rascally guile the parasite adds prudence. All, until there is none of them left, abandon the clay homes which would be their undoing, once the entrance was plugged up. The earthy retreat, so grateful to the tender skin, thanks to its polished coating, so free from humidity, thanks to its waterproof glaze, ought, one would think, to make an excellent waiting-place. The maggots will have none of it. Lest they should find themselves walled in when they become frail Gnats, they go away and disperse in the neighbourhood of the ascending pit. My digging operations, in fact, always reveal the pupæ outside the cells, never inside. I find them enshrined, one by one, in the body of the clayey earth, in a narrow niche which the emigrant worm has contrived to make for itself. Next spring, when the hour comes for leaving, the adult insect has but to creep through the rubbish, which is easy work. Another and no less imperative reason compels this change of abode on the parasite’s part. In July, a second generation of the Halictus is procreated. The Dipteron, reduced, on her side, to a single brood, remains in the pupa state and awaits the spring of the following year before effecting her transformation. The honey-gatherer resumes her work in the natal hamlet; she avails herself of the pits and cells constructed in the spring, saving no little time thereby. The whole elaborate structure has remained in good condition. It needs but a few repairs to make the old house habitable. Now what would happen if the Bee, so intent upon cleanliness, were to find a pupa in the cell which she is sweeping? She would treat the cumbersome object as she would a piece of old plaster. It would be no more to her than any other refuse, a bit of gravel, which, seized with the mandibles, crushed perhaps, would be sent to join the rubbish-heap outside. Once removed from the soil and exposed to the inclemencies of the weather, the pupa would inevitably perish.