Lastly, in all these egg-shells, after the hatching, we find inside them, quite close to the rim, that black mark in the shape of a broad arrow, of which we have already asked ourselves whether it is a trade-mark [[193]]or a sort of lock or bolt. The future will show us how far our guesses fall short of the reality.
The eggs are never sown at random. The whole batch is laid in a close-packed group, in regular ranks of varying lengths, so that they make a sort of mosaic of beads firmly fixed to their common support, usually a leaf. They adhere so firmly that we may brush the leaf with a camel-hair pencil, or even touch them with the finger, without in any way disturbing their beautiful arrangement. After the young have gone we find the open shells still in position, like so many little jam-pots standing in rows on a market-woman’s barrow.
Let me end by giving a few specific details. The eggs of the Black-horned Pentatoma (P. nigricorne) are cylindroid in form, the base being a segment of a sphere. The lid, bearing a broad white band at the edge, frequently, but not always, has in the centre a transparent protuberance, a sort of knob like that on the lid of a preserve-jar. Its entire surface is smooth and glossy, with no other ornament than its simplicity. The colour varies according to the degree of [[194]]maturity. When recently laid the eggs are of a uniform straw-yellow: later, owing to the gradual organization of the germ, they turn a pale orange, with a triangular bright-red patch in the centre of the lid. When empty they are a magnificent, pellucid opal-white, except the lid, which has become transparent as glass.
Of the clutches of eggs obtained the most numerous was a patch of nine rows, each containing about a dozen eggs. The total was thus about a hundred. But usually the number of eggs is smaller than this, amounting to only half as many or less. Groups containing about a score of eggs are not uncommon. The enormous difference between these extremes testifies to multiple layings at different spots, which, in view of the insect’s rapid flight, may be at quite a distance from one another. This detail will be of value when the time comes.
The Pale-Green Pentatoma (P. praesinum) moulds her eggs in little barrels, ovoid at the bottom and adorned over their whole surface with a network of fine polygonal meshes in relief. Their colour is a sooty brown, and, after the hatching, a very [[195]]light brown. The largest groups of eggs contain thirty or so. It is probably to this species that the eggs belong which first attracted my attention on a sprig of asparagus.
As for the Berry Pentatoma (P. baccarum) here we again have barrels with rounded ends, covered all over the surface with a tracery of meshes. At first they are opaque and dark; then, being empty, they become translucent and white or pale-pink. Of these eggs I find groups of fifty and others of fifteen or even less.
That blessed plant of the kitchen-gardens, the cabbage, gives me the Ornate Pentatoma (P. ornatum), striped black and red. The eggs of this species are the prettiest of all in colouring. They are like little casks with the two ends convex, especially the lower. The microscope shows us a surface engraved with pits, like those of a thimble, arranged with exquisite regularity. At the top and bottom of the cylinder there is a broad dull-black band; on the sides is a wide white belt with four large black spots symmetrically placed. The lid, surrounded with snow-white filaments and edged with white, swells into a black dome with a central white spot. [[196]]In short, a funeral urn, with its violent contrast of coal-black and creamy white. The Etruscans would have considered it a magnificent model for their burial vessels.
These eggs, with their funeral ornamentation, are arranged in small groups, generally in two rows. There are hardly a dozen all told: a fresh proof that the eggs must be laid in a number of batches and at different points; for the Cabbage Bug cannot limit herself to this paltry number when one of her relatives exceeds the hundred.
May is not over before the various batches of eggs collected and placed in tubes hatch out, first one and then another. Two or three weeks are enough to develop the germ. This is the time for constant vigilance, if I wish to understand the mechanism employed for the emergence and, above all, the function of the strange tool, with the three black arms, which I find in every shell, at the edge of the opening, once the new-born larva has departed.
Those eggs which are translucent from the outset—for example, those of the Black-horned Pentatoma—enable me, in the first place, to discover that the implement of unknown [[197]]use makes its appearance rather late, when the approaching deliverance is announced by a change in the colour of the lid. It is not, therefore, an original part of the egg, as this descended from the ovaries; it is elaborated during the process of development, and even at a somewhat advanced phase, when the little Bug has already been formed.