Cases of this kind occur too seldom to satisfy fully the curiosity of a seasoned observer. I should have liked to arrange the mist-screen myself and thus to try a few experiments bearing upon the dangerous crossing; but I was a stranger, a spectator by sheer chance; and all that I could do was to trust to luck, without interfering with the washing-operations and perhaps upsetting them. What a sorry idea the housewife engaged on that grave business would have had of my intelligence if I had ventured to touch her fire in order to worry a Wasp! “I’a pétan cièucle: little things please little minds,” she would have been sure to think. In the eyes of the peasant, to occupy one’s self with such small fry is a lunatic’s game, the amusement of a cracked mind. Once and once only fortune smiled upon me; but I was not ready to profit by it. The thing took place at my own house, by my own fireside and, as it happened, on a washing-day. I had not long been appointed to the Avignon grammar-school. It was close upon two o’clock; and in a few minutes the roll of the drum would summon me to display the properties of the Leyden jar to an audience of wool-gatherers. I was preparing to start, when I saw a strange, agile insect, with a slender body and a gourd-shaped abdomen slung at the end of a long thread, dart through the reek rising from the wash-tub. It was the Pelopæus, whom I saw for the first time with observant eyes. A novice still and anxious to become better-acquainted with my visitor, I fervently commended the insect to the watchful care of the household, begging them not to disturb it in my absence and to manage the fire in such a way as not to inconvenience it in its plucky work of building the walls of its nest right beside the flame. My wishes were carried out religiously. Things went better than I dared hope. On my return, the Pelopæus was continuing her mason’s work behind the steam of the wash-tub, which stood under the mantel of a wide chimney. Eager as I was to witness the construction of the cells, to identify the nature of the provisions, to follow the evolution of the larvæ, all of them biological details entirely new to me, I took good care not to raise the experimental obstacles which I should not fail to set in the path of instinct to-day: a good nest was the sole object that I coveted. Therefore, so far from creating fresh difficulties for the Pelopæus, I did my utmost to reduce those which she had to overcome. I raked the fire, making it much smaller, so as to decrease the volume of smoke in the Wasp’s building-yard; and for a good two hours I watched her diving through the cloud. Next day, the usual niggardly fire was burning intermittently; and there was nothing now to hamper the Pelopæus, who continued her work for some days and without further impediment completed the well-filled nest which was the object of my wishes.