The building-operations start again in the second week of July. The galleries are restored and lengthened; new cells are fashioned and the old ones repaired. Follow the provisioning, the laying of the eggs, the closing of the cells; and, before July is over, there is solitude again. Let me also say that, during the building-period, not a male appears in sight, a fact which adds further proof to that already supplied by my excavations.
With the high temperature of this time of the year, the development of the larvae makes rapid progress: a month is sufficient for the various stages of the metamorphosis. On the 24th of August there are once more signs of life above the burrows of the Cylindrical Halictus, but under very different conditions. For the first time, both sexes are present. Males, so easily recognized by their black livery and their slim abdomen adorned with a red ring, hover backwards and forwards, almost level with the ground. They fuss about from burrow to burrow. A few rare females come out for a moment and then go in again.
I proceed to make an excavation with my spade; I gather indiscriminately whatever I come across. Larvae are very scarce;pupae abound, as do perfect insects. The list of my captures amounts to eighty males and fifty-eight females. The males, therefore, hitherto impossible to discover, either on the flowers around or in the neighbourhood of the burrows, could be picked up to-day by the hundred, if I wished. They outnumber the females by about four to three; they are also further developed, in accordance with the general rule, for most of the backward pupae give me only females.
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.
A little spade-work soon turns suspicion into certainty. I unearth a sufficient number of couples to prove to me that the sexes come together underground. When the marriage is consummated, the red-belted one quits the spot and goes to die outside the burrow, after dragging from flower to flower the bit of life that remains to him.
The other shuts herself up in her cell, there to await the return of the month of May.
September is spent by the Halictus solely in nuptial celebrations.
Whenever the sky is fine, I witness the evolutions of the males above the burrows, with their continual entrances and exits; should the sun be veiled, they take refuge down the passages. The more impatient, half-hidden in the pit, show their little black heads outside, as though peeping for the least break in the clouds that will allow them to pay a brief visit to the flowers round about. They also spend the night in the burrows. In the morning, I attend their levee; I see them put their head to the window, take a look at the weather and then go in again until the sun beats on the encampment.
