The Halictus opens up another question, connected with one of life's obscurest problems. Let us go back five-and-twenty years. I am living at Orange. My house stands alone among the fields. On the other side of the wall enclosing our yard, which faces due south, is a narrow path overgrown with couch-grass. The sun beats full upon it; and the glare reflected from the whitewash of the wall turns it into a little tropical corner, shut off from the rude gusts of the north-west wind.
Here the Cats come to take their afternoon nap, with their eyes half-closed; here the children come, with Bull, the House-dog; here also come the haymakers, at the hottest time of the day, to sit and take their meal and whet their scythes in the shade of the plane-tree;here the women pass up and down with their rakes, after the hay-harvest, to glean what they can on the niggardly carpet of the shorn meadow. It is therefore a very much frequented footpath, were it only because of the coming and going of our household: a thoroughfare ill-suited, one would think, to the peaceful operations of a Bee; and nevertheless it is such a very warm and sheltered spot and the soil is so favourable that every year I see the Cylindrical Halictus (H.
cylindricus, FAB.) hand down the site from one generation to the next. It is true that the very matutinal, even partly nocturnal character of the work makes the insect suffer less inconvenience from the traffic.
The burrows cover an extent of some ten square yards, and their mounds, which often come near enough to touch, average a distance of four inches at the most from one another. Their number is therefore something like a thousand. The ground just here is very rough, consisting of stones and dust mixed with a little mould and held together by the closely interwoven roots of the couch-grass. But, owing to its nature, it is thoroughly well drained, a condition always in request among Bees and Wasps that have underground cells.
Let us forget for a moment what the Zebra Halictus and the Early Halictus have taught us. At the risk of repeating myself a little, Iwill relate what I observed during my first investigations. The Cylindrical Halictus works in May. Except among the social species, such as Common Wasps, Bumble-bees, Ants and Hive-bees, it is the rule for each insect that victuals its nests either with honey or game to work by itself at constructing the home of its grubs. Among insects of the same species there is often neighbourship; but their labours are individual and not the result of co-operation. For instance, the Cricket-hunters, the Yellow-winged Sphex, settle in gangs at the foot of a sandstone cliff, but each digs her own burrow and would not suffer a neighbour to come and help in piercing the home.
In the case of the Anthophorae, an innumerable swarm takes possession of a sun-scorched crag, each Bee digging her own gallery and jealously excluding any of her fellows who might venture to come to the entrance of her hole. The Three-pronged Osmia, when boring the bramble-stalk tunnel in which her cells are to be stacked, gives a warm reception to any Osmia that dares set foot upon her property.
Let one of the Odyneri who make their homes in a road-side bank mistake the door and enter her neighbour's house: she would have a bad time of it! Let a Megachile, returning with her leafy disk in her legs, go into the wrong basement: she would be very soon dislodged!
So with the others: each has her own home, which none of the others has the right to enter. This is the rule, even among Bees and Wasps established in a populous colony on a common site. Close neighbourhood implies no sort of intimate relationship.
Great therefore is my surprise as I watch the Cylindrical Halictus'
operations. She forms no society, in the entomological sense of the word: there is no common family; and the general interest does not engross the attention of the individual. Each mother occupies herself only with her own eggs, builds cells and gathers honey only for her own larvae, without concerning herself in any way with the upbringing of the others' grubs. All that they have in common is the entrance-door and the goods-passage, which ramifies in the ground and leads to different groups of cells, each the property of one mother. Even so, in the blocks of flats in our large towns, one door, one hall and one staircase lead to different floors or different portions of a floor where each family retains its isolation and its independence.
This common right of way is extremely easy to perceive at the time for victualling the nests. Let us direct our attention for a while to the same entrance-aperture, opening at the top of a little mound of earth freshly thrown up, like that accumulated by the Ants during their works. Sooner or later we shall see the Halicti arrive with their load of pollen, gathered on the Cichoriaceae of the neighbourhood.
Usually, they come up one by one; but it is not rare to see three, four or even more appearing at the same time at the mouth of one burrow. They perch on the top of the mound and, without hurrying in front of one another, with no sign of jealousy, they dive down the passage, each in her turn. We need but watch their peaceful waiting, their tranquil dives, to recognize that this indeed is a common passage to which each has as much right as another.
When the soil is exploited for the first time and the shaft sunk slowly from the outside to the inside, do several Cylindrical Halicti, one relieving the other, take part in the work by which they will afterwards profit equally? I do not believe it for a moment. As the Zebra Halictus and the Early Halictus told me later, each miner goes to work alone and makes herself a gallery which will be her exclusive property. The common use of the passage comes presently, when the site, tested by experience, is handed down from one generation to another.
