Fabre's Book of Insects

by Jean-Henri Fabre

If you have paid attention to this story of the Anthrax Fly, you must have noticed that it is incomplete. The Fox in the fable saw how the Lion’s visitors entered his den, but did not see how they went out. With us the case is reversed: we know the way out of the Mason-bee’s fortress, but we do not know the way in. To leave the cell whose owner it has eaten, the Anthrax becomes a boring-tool. When the exit-tunnel is opened this tool splits like a pod bursting in the sun, and from the strong framework there escapes a dainty Fly. A soft bit of fluff that contrasts strangely with the roughness of the prison whence it comes. On this point we know pretty well what there is to know. But the entrance of the grub into the cell puzzled me for a quarter of a century.

It is plain that the mother cannot place her egg in the Bee’s cell, which is closed and barricaded with a cement wall. To pierce it she would have to become a boring-tool once more, and get into the cast-off rags which she left at the doorway of the exit-tunnel. She would have [[263]]to become a pupa again. For the full-grown Fly has no claws, nor mandibles, nor any implement capable of working its way through the wall.

Can it be, then, the grub that makes its own way into the storeroom, that same grub that we have seen sucking the life out of the Bee’s larva? Let us call the creature to mind: a little oily sausage, which stretches and curls up just where it lies, without being able to shift its position. Its body is a smooth cylinder, its mouth a circular lip. It has no means whatever of moving; not even a hair or a wrinkle to enable it to crawl. It can do nothing but digest its food. It is even less able than the mother to make its way into the Mason-bee’s dwelling. And yet its provisions are there: they must be reached: it is a matter of life and death. How does the Fly set about it? In the face of this puzzle I resolved to attempt an almost impossible task and watch the Anthrax from the moment it left the egg.

Since these Flies are not really plentiful in my own neighbourhood I made an expedition to Carpentras, the dear little town where I spent my twentieth year. The old college where I made my first attempts as a teacher was unchanged in appearance. It still looked like a penitentiary. In my early days it was considered unwholesome for boys to be gay and active, so our system of education applied the remedy of melancholy and gloom. Our houses of instruction were above all houses [[264]]of correction. In a yard between four walls, a sort of bear-pit, the boys fought to make room for their games under a spreading plane-tree. All round it were cells like horseboxes, without light or air: those were the class-rooms.

I saw, too, the shop where I used to buy tobacco as I came out of the college; and also my former dwelling, now occupied by monks. There, in the embrasure of a window, sheltered from profane hands, between the closed outer shutters and the panes, I kept my chemicals—bought for a few sous saved out of the housekeeping money. My experiments, harmless or dangerous, were made on a corner of the fire, beside the simmering broth. How I should love to see that room again, where I pored over mathematical problems; and my familiar friend the blackboard, which I hired for five francs a year, and could never buy outright for want of the necessary cash!

But I must return to my insects. My visit to Carpentras, unfortunately, was made too late in the year to be very profitable. I saw only a few Anthrax Flies hovering round the face of the cliff. Yet I did not despair, because it was plain that these few were not there to take exercise, but to settle their families.

So I took my stand at the foot of the rock, under a broiling sun, and for half a day I followed the movements of my Flies. They flitted quietly in front of the slope, a few inches away from the earthly covering. [[265]]They went from one Bee’s nest to another, but without attempting to enter. For that matter, the attempt would be useless, for the galleries are too narrow to admit their spreading wings. So they simply explore the cliff, going to and fro, and up and down, with a flight that was now sudden, now smooth and slow. From time to time I saw one of them approach the wall and touch the earth suddenly with the tip of her body. The proceeding took no longer than the twinkling of an eye. When it was over the insect rested a moment, and then resumed flight.

I was certain that, at the moment when the Fly tapped the earth, she laid her eggs on the spot. Yet, though I rushed forward and examined the place with my lens, I could see no egg. In spite of the closest attention I could distinguish nothing. The truth is that my state of exhaustion, together with the blinding light and scorching heat, made it difficult for me to see anything. Afterwards, when I made the acquaintance of the tiny thing that comes out of that egg, my failure no longer surprised me: for even in the leisure and peace of my study I have the greatest difficulty in finding the infinitesimal creature. How then could I see the egg, worn out as I was under the sun-baked cliff?

None the less I was convinced that I had seen the Anthrax Flies strewing their eggs, one by one, on the spots frequented by the Bees who suit their grubs. They [[266]]take no precaution to place the egg under cover, and indeed the structure of the mother makes any such precaution impossible. The egg, that delicate object, is laid roughly in the blazing sun, among grains of sand, in some wrinkle of the chalk. It is the business of the young grub to manage as best it can.

The next year I continued my investigations, this time on the Anthrax of the Chalicodoma, a Bee that abounds in my own neighbourhood. Every morning I took the field at nine o’clock, when the sun begins to be unendurable. I was prepared to come back with my head aching from the glare, if only I could bring home the solution of my puzzle. The greater the heat, the better my chances of success. What gives me torture fills the insect with delight; what prostrates me braces the Fly.