What can this valve be which, descending or ascending in the cylinder of the pit, after the fashion of a piston, opens and closes the house at each departure and at each arrival? It is an Halictus, who has become the portress of the establishment. With her large head, she makes an impassable barrier at the top of the entrance-hall. If any one belonging to the house wants to go in or out, she 'pulls the cord,' that is to say, she withdraws to a spot where the gallery becomes wider and leaves room for two. The other passes. She then at once returns to the orifice and blocks it with the top of her head.
Motionless, ever on the look-out, she does not leave her post save to drive away importunate visitors.
Let us profit by her brief appearances outside to take a look at her.
We recognize in her an Halictus similar to the others, which are now busy harvesting; but the top of her head is bald and her dress is dingy and thread-bare. All the nap is gone; and one can hardly make out the handsome stripes of red and brown which she used to have.
These tattered, work-worn garments make things clear to us.
This Bee who mounts guard and performs the office of a portress at the entrance to the burrow is older than the others. She is the foundress of the establishment, the mother of the actual workers, the grandmother of the present grubs. In the springtime of her life, three months ago, she wore herself out in solitary labours. Now that her ovaries are dried up, she takes a well-earned rest. No, rest is hardly the word. She still works, she assists the household to the best of her power. Incapable of being a mother for a second time, she becomes a portress, opens the door to the members of her family and makes strangers keep their distance.
The suspicious Kid (In La Fontaine's fable, "Le Loup, la Chevre et le Chevreau."--Translator's Note.), looking through the chink, said to the Wolf:
'Show me a white foot, or I shan't open the door.'
No less suspicious, the grandmother says to each comer:
'Show me the yellow foot of an Halictus, or you won't be let in.'
None is admitted to the dwelling unless she be recognized as a member of the family.
See for yourselves. Near the burrow passes an Ant, an unscrupulous adventuress, who would not be sorry to know the meaning of the honeyed fragrance that rises from the bottom of the cellar.
"Be off, or you'll catch it!'says the portress, wagging her neck.
As a rule the threat suffices. The Ant decamps. Should she insist, the watcher leaves her sentry-box, flings herself upon the saucy jade, buffets her and drives her away. The moment the punishment has been administered, she returns to her post.
Next comes the turn of a Leaf-cutter (Megachile albocincta, PEREZ), which, unskilled in the art of burrowing, utilizes, after the manner of her kin, the old galleries dug by others. Those of the Zebra Halictus suit her very well, when the terrible Gnat has left them vacant for lack of heirs. Seeking for a home wherein to stack her robinia-leaf honey-pots, she often makes a flying inspection of my colonies of Halicti. A burrow seems to take her fancy; but, before she sets foot on earth, her buzzing is noticed by the sentry, who suddenly darts out and makes a few gestures on the threshold of her door. That is all. The Leaf-cutter has understood. She moves on.
Sometimes, the Megachile has time to alight and insert her head into the mouth of the pit. In a moment, the portress is there, comes a little higher and bars the way. Follows a not very serious contest.
The stranger quickly recognizes the rights of the first occupant and, without insisting, goes to seek an abode elsewhere.
An accomplished marauder (Caelioxys caudata, SPIN.), a parasite of the Megachile, receives a sound drubbing under my eyes. She thought, the feather-brain, that she was entering the Leaf-Cutter's establishment! She soon finds out her mistake; she meets the door-keeping Halictus, who administers a sharp correction. She makes off at full speed. And so with the others which, through inadvertence or ambition, seek to enter the burrow.
The same intolerance exists among the different grandmothers. About the middle of July, when the animation of the colony is at its height, two sets of Halicti are easily distinguishable: the young mothers and the old. The former, much more numerous, brisk of movement and smartly arrayed, come and go unceasingly from the burrows to the fields and from the fields to the burrows. The latter, faded and dispirited, wander idly from hole to hole. They look as though they had lost their way and were incapable of finding their homes. Who are these vagabonds? I see in them afflicted ones bereft of a family through the act of the odious Gnat. Many burrows have been altogether exterminated. At the awakening of summer, the mother found herself alone. She left her empty house and went off in search of a dwelling where there were cradles to defend, a guard to mount.
But those fortunate nests already have their overseer, the foundress, who, jealous of her rights, gives her unemployed neighbour a cold reception. One sentry is enough; two would merely block the narrow guard-room.
I am privileged at times to witness a fight between two grandmothers.
When the tramp in quest of employment appears outside the door, the lawful occupant does not move from her post, does not withdraw into the passage, as she would before an Halictus returning from the fields. Far from making way, she threatens the intruder with her feet and mandibles. The other retaliates and tries to force her way in notwithstanding. Blows are exchanged. The fray ends by the defeat of the stranger, who goes off to pick a quarrel elsewhere.
