To begin with, inspected cell by cell, my bundle of reeds tells me that the big larvæ, those which have acquired their full development, very often adhere by their hinder part to the walls of the cell. The meaning of this detail is evident. Captured when the metamorphosis was at hand, the grub, despite the blows of the stiletto, has made its usual preparations: it has hung itself firmly to the adjoining support, the earthen partition or the tube of the reed, just as it fastens itself to the poplar-leaf. The creature is so fresh in appearance and its anal adhesion is so accurate that I actually hope to see the victim’s skin split and the nymph appear. My hope is not at all exaggerated; it is based on facts no less curious which I shall describe later. Events did not respond to the probabilities on which I all but relied. When removed from the charnel-house with their point of support and put in a safe place, none of the larvæ settled for the nymphosis went beyond the preparatory action. This action in itself, however, is eloquent enough: it tells us that a remnant of life faintly animates the grub, since it retains power to make the necessary arrangements for the transformation. That the grub is no corpse is revealed in another manner. I place in glass tubes, with a plug of cotton, twelve larvæ removed from the Odynerus’ larders. The sign of latent life is the creature’s freshness and its hue, a soft pinky white; the sign of death and corruption is a brown colouring. Well, eighteen days later one of the grubs begins to turn brown. A second is seen to be dead in thirty-one days. In forty-four days, six are still fresh and full. Finally, the last continues in good condition for two months, from the 16th of June to the 15th of August. It goes without saying that, under the same conditions, larvæ which are really dead and unbruised, larvæ asphyxiated with bisulphide of carbon, turn brown in a few days. As I should have expected, the laying-peculiarities of the Nest-building Odynerus are precisely identical with those of O. reniformis, the object of my earlier observations. I again witness, with the satisfaction that results from verifying an interesting fact, the curious arrangements already described. The egg is laid first, right at the back of the cell. Next comes the stacking of the provisions in the order of capture. In this way the eating proceeds from the oldest to the most recent.