Once the two sexes had appeared, I expected a third generation that would spend the winter in the larval state and recommence in May the annual cycle which I have just described. My anticipation proved to be at fault. Throughout September, when the sun beats upon the burrows, I see the males flitting in great numbers from one shaft to the other. Sometimes a female appears, returning from the fields, but with no pollen on her legs. She seeks her gallery, finds it, dives down and disappears. The males, as though indifferent to her arrival, offer her no welcome, do not harass her with their amorous pursuits; they continue to visit the doors of the burrows with a winding and oscillating flight. For two months, I follow their evolutions. If they set foot on earth, it is to descend forthwith into some gallery that suits them. It is not uncommon to see several of them on the threshold of the same burrow. Then each awaits his turn to enter; they are as peaceable in their relations as the females who are joint owners of a burrow. At other times, one wants to go in as a second is coming out. This sudden encounter produces no strife. The one leaving the hole withdraws a little to one side to make enough room for two; the other slips past as best he can. These peaceful meetings are all the more striking when we consider the usual rivalry between males of the same species. No rubbish-mound stands at the mouth of the shafts, showing that the building has not been resumed; at the most, a few crumbs of earth are heaped outside. And by whom, pray? By the males and by them alone. The lazy sex has bethought itself of working. It turns navvy and shoots out grains of earth that would interfere with its continual entrances and exits. For the first time I witness a custom which no Hymenopteron had yet shown me: I see the males haunting the interior of the burrows with an assiduity equalling that of the mothers employed in nest-building. The cause of these unwonted operations soon stands revealed. The females seen flitting above the burrows are very rare; the majority of the feminine population remain sequestered under ground, do not perhaps come out once during the whole of the latter part of summer. Those who do venture out go in again soon, empty-handed of course and always without any amorous teasing from the males, a number of whom are hovering above the burrows. On the other hand, watch as carefully as I may, I do not discover a single act of pairing out of doors. The weddings are clandestine, therefore, and take place under ground. This explains the males' fussy visits to the doors of the galleries during the hottest hours of the day, their continual descents into the depths and their continual reappearances. They are looking for the females cloistered in the retirement of the cells.