The book was devoured—I can use no other word. There I learned the name of my black bee, and there I read for the first time details of the habits of insects, and found, with what seemed to my eyes an aureole round them, the venerated names of Réaumur, Huber, Léon Dufour; and while I turned the pages for the hundredth time, a voice whispered vaguely, “Thou too shalt be a historian of animals!” Naïve illusions! where are you? But let us banish these recollections, both sweet and sad, and come to the doings of our black bee.
Chalicodoma, house of pebbles, rough-cast mortar, a name which would be perfect did it not look odd to any one not well up in Greek. It is a [[277]]name applied to those Hymenoptera that build cells with materials such as we use for our dwellings. It is masonry, but made by a rustic workman, better used to dried clay than to hewn stone. A stranger to scientific classification (and this causes great obscurity in some of his memoirs), Réaumur called the worker after the work, and named our builders in dried clay Mason Bees, which paints them exactly. We have two kinds, C. muraria, whose history is admirably given by Réaumur, and C. sicula, which is not special to the land of Etna, as the name suggests, but is found in Greece, Algeria, and the Mediterranean region of France, especially in the department of Vaucluse, where in May it is one of the most common Hymenoptera. The two sexes of C. muraria are so unlike in colouring that a novice observing both coming out of the same nest would take them for strangers to one another. The female is of a splendid velvet black, with dark violet wings; in the male the black velvet is replaced by a bright iron-red fleece. The second species—a much smaller one—has not this difference of colour, both sexes wearing the same costume—a general mixture of brown, red, and ashy tints. Both begin to build in the beginning of May. The wing-tips, washed with violet on a bronze ground, faintly recall the rich purple of the first species.
As Réaumur tells us, C. muraria in the northern provinces chooses as the place to fix her nest a wall well exposed to the sun and not plastered, as the plaster might come off and endanger her cells. She only entrusts her constructions to a solid foundation, such as a bare stone. I see that she is equally [[278]]prudent in the south, but, for some reason unknown to me, she generally chooses some other base than the stone of a wall. A rolled pebble, often hardly larger than one’s fist,—one of those with which the waters of the glacial period covered the terraces of the Rhône valley,—is her favourite support. The great ease with which such a one is found may influence her; all our slightly raised plateaux, all our arid thyme-clad ground, are but heaped pebbles cemented with red earth. In the valleys the bee can also use the stones gathered in torrent beds; near Orange, for instance, her favourite spots are the alluviums of the Aygues, with their stretches of rolled boulders no longer visited by water. Or if a pebble be wanting, she will establish her nest on a boundary stone or an enclosing wall.
Chalicodoma sicula has a yet greater variety of choice. Her favourite position is under a tile projecting from the edge of a roof. There is scarcely a little dwelling in the fields that does not thus shelter her nests. There, every spring, she establishes populous colonies, whose masonry, transmitted from one generation to another, and yearly enlarged, finally covers a very considerable surface. I have seen such a one under the tiles of a shed, which spread over five or six square yards. When the colony were hard at work, their number and humming fairly made one dizzy. The underpart of a balcony pleases them equally, or the frame of an unused window,—above all, if closed by a sun-shutter, which offers a free passage. But these are great meeting-places, where labour, each for herself, hundreds and thousands of workers. If alone, which not seldom occurs, Chalicodoma [[279]]sicula establishes herself in the first little spot she can find, so long as it has a solid basis and heat. As for the nature of this basis it matters little. I have seen nests built on bare stones and brick, on a shutter, and even on the glass panes in a shed. One thing only does not suit the bee—namely, the stucco of our houses. Prudent, like her retainer C. muraria, she would fear ruin to her cells did she entrust them to a support which might fall.
Finally, for reasons which I cannot yet satisfactorily explain, C. sicula often entirely changes her manner of building, turning her heavy mortar dwelling, which seems to require a rock to support it, into an aerial one, hung to a bough. A bush in a hedge,—no matter what—hawthorn, pomegranate, or Paliurus,—offers a support, usually about the height of a man, Ilex and elm give a greater height. The bee chooses in some thicket a bough about as thick as a straw, and constructs her edifice on this narrow base with the same mortar which would be used under a balcony or the projecting edge of a roof. When finished, the nest is a ball of earth, traversed literally by the bough. If made by a single insect it is the size of an apricot, and of a fist if several have worked at it; but this seldom occurs.
Both species use the same materials, a calcareous clay, mixed with a little sand and kneaded with the mason’s own saliva. Damp spots which would facilitate labour and spare saliva to mix mortar are disdained by the Chalicodoma, which refuses fresh earth for building, just as our builders refuse old plaster and lime. Such materials when soaked with humidity would not hold properly. What is needed is a dry [[280]]powder, which readily absorbs the disgorged saliva, and forms with the albuminous principles of this liquid a kind of Roman cement, hardening quickly,—something like what we obtain with quicklime and white of egg.
[To face p. 280.
MASON BEES—CHALICODOMA SICULA AND NEST
A beaten road, formed of calcareous boulders crushed by passing wheels into a smooth surface like paving stones, is the quarry whence Chalicodoma sicula prefers to get mortar; whether she builds on a branch, in a hedge, or under the jutting roof of some rural habitation, it is always from a neighbouring path, or a road, or the highway, that she seeks materials—indifferent to the constant passing of beasts and travellers. You should see the active bee at work when the road is dazzling white in the hot sunshine. Between the neighbouring farm where she is building and the road where the mortar is prepared, there is the deep hum of the bees perpetually crossing each other as they come and go. The air seems traversed by constant trails of smoke, so rapid and direct is their flight. Those who go carry away a pellet of mortar as big as small shot; those who come settle on the hardest and driest spots. Their whole body vibrates as they scratch with the tips of their mandibles, and rake with their forefeet to extract atoms of earth and grains of sand, which, being rolled between their teeth, become moist with saliva and unite. They work with such ardour that they will let themselves be crushed under the foot of a passer-by rather than move. Chalicodoma muraria, however, which seeks solitude, far from human habitation, is rarely seen on beaten paths; perhaps they are too distant from the places where she builds. If [[281]]she can find dry earth, rich in small gravel, near the boulder chosen as the basis of her nest, she is contented. She may either make quite a new nest in a spot hitherto unoccupied, or over the cells of an old one, after repairing them. Let us consider the first case.