I was above all anxious to ascertain whether the egg was pendulous, that is to say, whether it hung by a thread at one point of the cell, in accordance with what I had learnt from the Eumenes and from O. reniformis. A kinswoman of the latter must, I felt certain beforehand, conform to the method of the suspension-cord; but there was reason to fear that the journey from Orange and the jolting of the cart might have broken the delicate pendulum. I recalled my anxieties, my minute precautions, during the removal of the cells with the egg of O. reniformis swinging from the ceiling. The cart, ignorant of its precious burden, might have undone everything. But no, to my great surprise. In most of the cells which were sufficiently recent I find the egg in place, slung sometimes from the arched roof of the reed, sometimes from the upper edge of the partition, by a thread which is just visible and about one twenty-fifth of an inch long. The egg is itself cylindrical and measures about an eighth of an inch. The reeds, opened wide and placed in glass tubes, enable me to witness the hatching, which takes place three days after the closing of the cell and probably four days after the laying. I see the new-born grub enclosed almost wholly, head downwards, in the sheath provided by the pellicle of the egg. Very slowly it slides forward in this scabbard and the suspension-cord stretches to the same extent. It is extremely fine in the part consisting of the original thread, but very much thicker in the portion resulting from the slough of the egg. The grub’s head reaches the nearest piece of game at one point or another; and the fragile creature takes its first mouthful. If anything startles it, if I tap the reed, it lets go and withdraws a little way into the sheath of the egg; then, reassured, it once more glides forward and resumes the point attacked. At other times a jerk leaves it indifferent. This suspension-stage of the new-born larva continues for about twenty-four hours, after which the grub, now somewhat fortified, lets itself drop and eats in the ordinary manner. The victuals last it for twelve days. Immediately afterwards comes the working of the cocoon, in which the insect remains, a yellow larva, until next May. It would be tedious to follow the Odynerus in its career of eating and weaving. The consumption of dishes highly spiced with nitrobenzene and the spinning of the cocoon, of a fine amber-coloured fabric, involve nothing so remarkable as to deserve special mention. Before leaving this subject, I will state a problem which the pendulous egg sets to the embryogenist. Every insect’s egg, if cylindrical in form, has two poles, the front and back, the cephalic and the anal pole. By which of the two does the insect see the light?