The cage was in darkness, almost in the open air. From time to time I visited it with a net and lantern. The visitors were captured, inspected, and immediately released in a neighbouring room, of which I closed the door. This gradual elimination allowed me to count the visitors exactly without danger of counting the same butterfly more than once. Moreover, the provisional prison, large and bare, in no wise harmed or endangered the prisoners; they found a quiet retreat there and ample space. Similar precautions were taken during the rest of my experiments.
After half-past ten no more arrived. The reception was over. Total, twenty-five males captured, of which one only was deprived of its antennæ. So of the six operated on earlier in the day, which were strong enough to leave my study and fly back to the fields, only one had returned to the cage. A poor result, in which I could place no confidence as proving whether the antennæ did or did not play a directing part. It was necessary to begin again upon a larger scale.
Next morning I visited the prisoners of the day before. What I saw was not encouraging. A large number were scattered on the ground, almost inert. Taken between the fingers, several of them gave scarcely a sign of life. Little was to be hoped from these, it would seem. Still, I determined to try; perhaps they would regain their vigour at the lover's hour.
The twenty-four prisoners were all subjected to the amputation of their antennæ. The one operated on the day before was put aside as dying or nearly so. Finally the door of the prison was left open for the rest of the day. Those might leave who could; those could join in the carnival who were able. In order to put those that might leave the room to the test of a search, the cage, which they must otherwise have encountered at the threshold, was again removed, and placed in a room of the opposite wing, on the ground floor. There was of course free access to this room.
Of the twenty-four lacking their antennæ sixteen only left the room. Eight were powerless to do so; they were dying. Of the sixteen, how many returned to the cage that night? Not one. My captives that night were only seven, all new-comers, all wearing antennæ. This result seemed to prove that the amputation of the antennæ was a matter of serious significance. But it would not do to conclude as yet: one doubt remained.
"A fine state I am in! How shall I dare to appear before the other dogs?" said Mouflard, the puppy whose ears had been pitilessly docked. Had my butterflies apprehensions similar to Master Mouflard's? Deprived of their beautiful plumes, were they ashamed to appear in the midst of their rivals, and to prefer their suits? Was it confusion on their part, or want of guidance? Was it not rather exhaustion after an attempt exceeding the duration of an ephemeral passion? Experience would show me.
On the fourth night I took fourteen new-comers and set them apart as they came in a room in which they spent the night. On the morrow, profiting by their diurnal immobility, I removed a little of the hair from the centre of the corselet or neck. This slight tonsure did not inconvenience the insects, so easily was the silky fur removed, nor did it deprive them of any organ which might later on be necessary in the search for the female. To them it was nothing; for me it was the unmistakable sign of a repeated visit.
This time there were none incapable of flight. At night the fourteen shavelings escaped into the open air. The cage, of course, was again in a new place. In two hours I captured twenty butterflies, of whom two were tonsured; no more. As for those whose antennæ I had amputated the night before, not one reappeared. Their nuptial period was over.
Of fourteen marked by the tonsure two only returned. Why did the other twelve fail to appear, although furnished with their supposed guides, their antennæ? To this I can see only one reply: that the Great Peacock is promptly exhausted by the ardours of the mating season.