My notes are unanimous on this point. The number of eggs laid on a pod always exceeds, and [[192]]often in a scandalous fashion, the number of peas available. However scanty the food-wallet may be, the guests are superabundant. Dividing the number of eggs perceived on a given pod by that of the peas inside it, I find from five to eight claimants for each pea; I find as many as ten; and there is nothing to tell me that the prodigality does not go farther still. Many are called, but few are chosen! Why all these supernumeraries, who are necessarily excluded from the banquet for want of space?
The eggs are a fairly bright amber-yellow, cylindrical in form, smooth and rounded at both ends. They are a millimetre long at most.[5] Each of them is fixed to the pod by a thin network of threads of coagulated albumen. Neither the rain nor the wind can loosen their hold.
The mother often emits them two at a time, one above the other; often also the uppermost of the pair succeeds in hatching, whereas the lower fades and perishes. What did this latter lack, to produce a grub? A sun-bath, perhaps, the gentle incubation of which the upper egg robs it. Whether through the effect of the untimely screen that overshadows it, or for some other reason, the elder of the eggs in a group of two rarely follows the normal course. It withers on the pod, dead before it has come to life.
There are exceptions to this premature end. [[193]]Sometimes the twin eggs develop equally well; but these instances are so rare that the family of the Bruchus would be reduced by nearly one-half if the binary system were a fixed rule. To the detriment of the peas and to the Weevil’s advantage there is one thing that lessens this destructive factor: the eggs are laid one by one and in separate places.
A recent hatching is marked by a whitish, winding little ribbon, which raises and fades the skin of the pod near the sloughed egg-shell. It is the work of the new-born larva and is a subcutaneous tunnel along which the tiny creature wends its way in search of a point through which to penetrate. When it has found this spot, the grub, measuring hardly a millimetre and pale-bodied, with a black cap, pierces the outer wrapper and dives into the capacious sheath of the pod.
It reaches the peas and perches on the nearest. I watch it through the magnifying-glass, exploring its globe, its world. It sinks a well at right angles to the sphere. I see some which, half-way down, wriggle their tails to stimulate their efforts. After a short spell of work, the miner disappears and is at home.
The entrance-hole is minute, but is easily recognized at any time by its brown colouring against the pale-green or yellow-green background of the pea. It has no fixed site; we see it more or less anywhere on the surface of the pea, excepting [[194]]generally on the lower half, that is to say, the hemisphere whose pole is formed by the base of the funicular cord.
It is precisely in this part that the germ is found which will not be consumed and will remain capable of developing into an embryo plant, in spite of the large hole made by the adult insect in leaving. Why is this portion left unscathed? What are the reasons that safeguard the germ of the exploited seed?
It goes without saying that the Bruchus does not consider the gardener. The pea is meant for it and none other. In refusing to take the few bites which would entail the death of the seed, it has no intention of reducing the damage. It abstains from other motives.
Remark that the peas touch at the sides, where they are pressed one against the other. The grub seeking the point of attack cannot move about at its ease. Remark also that the lower pole rests upon the umbilical excrescence and opposes to any attempt at boring difficulties which do not exist in the parts protected by the skin alone. It is even possible that this umbilicus, which is differently organized, contains special juices distasteful to the little larva.