There were plenty of the nests I wanted, but I could not see a single Anthrax on their surface. Not one settled in front of me to lay her egg. At most, from time to time, I could see one passing far away, with an impetuous rush. I would lose her in the distance; and that was all. It was impossible to be present at the laying of the egg. In vain I enlisted the services of the small boys who keep the sheep in our meadows, and talked to them of a big black Fly and the nests on which she ought to settle. By the end of August my last illusions were dispelled. Not one of us had succeeded in seeing the big black Fly perching on the dome of the Mason-bee. The reason is, I believe, that she never perches there. She comes and goes in every direction across the stony plain. Her practised eye can detect, as she flies, the earthen dome which she is seeking, and having found it she swoops down, leaves her egg on it, and makes off without setting foot on the ground. Should she take a rest it will be elsewhere, on the soil, on a stone, on a tuft of lavender or thyme. It is no wonder that neither I nor my young shepherds could find her egg. Meanwhile I searched the Mason-bees’ nests for grubs just out of the egg. My shepherds procured me heaps of the nests, enough to fill baskets and baskets; and these I inspected at leisure on my work-table. I took the cocoons from the cells, and examined them within and without: my lens explored their innermost recesses, the sleeping larva, and the walls. Nothing, nothing, nothing! For a fortnight and more nests were searched and rejected, and heaped up in a corner. My study was crammed with them. In vain I ripped up the cocoons; I found nothing. It needed the sturdiest faith to make me persevere. At last I saw, or seemed to see, something move on the Bee’s larva. Was it an illusion? Was it a bit of down stirred by my breath? It was not an illusion; it was not a bit of down; it was really and truly a grub! But at first I thought the discovery unimportant, because I was so greatly puzzled by the little creature’s appearance. In a couple of days I was the owner of ten such worms and had placed each of them in a glass tube, together with the Bee-grub on which it wriggled. It was so tiny that the least fold of skin concealed it from my sight. After watching it one day through the lens I sometimes failed to find it again on the morrow. I would think it was lost: then it would move, and become visible once more. For some time the belief had been growing in me that the Anthrax had two larval forms, a first and a second, the second being the form I knew, the grub we have already seen at its meals. Was this new discovery, I asked myself, the first form? Time showed me that it was. For at last I saw my little worms transform themselves into the grub I have already described, and make their first start at draining their victims with kisses. A few moments of satisfaction like those I then enjoyed make up for many a weary hour.