When June comes, I often meet young Dectici in the fields. Some are already half their adult size, which is evidence of an early appearance dating back to the first fine days of the year. Nevertheless my jar shows no signs of any imminent hatching. I find the eggs just as I gathered them nine months ago, neither wrinkled nor tarnished, wearing, on the contrary, a most healthy look. What causes this indefinitely prolonged delay?
A suspicion occurs to me. The eggs of the Grasshopper tribe are planted in the earth like seeds. They are there exposed, without any kind of protection, to the watery influence of the snow and the rain. Those [[240]]in my jar have spent two-thirds of the year in a state of comparative dryness. Perhaps, in order to hatch, they lack what grain absolutely needs in order to sprout. Animal seeds as they are, they may yet require under earth the moisture necessary to vegetable seeds. Let us try.
I place at the bottom of some glass tubes, to enable me to make certain observations which I have in mind, a pinch of backward eggs taken from my collection; and on the top I heap lightly a layer of very fine, damp sand. The receptacle is closed with a plug of wet cotton, which will maintain a constant moisture in the interior. The column of sand measures about an inch, which is very much the depth at which the ovipositor places the eggs. Any one seeing my preparations and unacquainted with their object would hardly suspect them of being incubators; he would be more likely to think them the apparatus of a botanist who was experimenting with seeds.
My anticipation was correct. Favoured by the high temperature of the summer solstice, the Grasshopper seed does not take long to sprout. The eggs swell; the front end of each is spotted with two dark dots, [[241]]the rudiments of the eyes. It is quite evident that the bursting of the shell is near at hand.
I spend a fortnight in keeping a tedious watch at every hour of the day: I have to surprise the young Decticus actually leaving the egg, if I want to solve a question that has long been vexing my mind. The question is this: the Grasshopper’s egg is buried at a varying depth, according to the length of the ovipositor or dibble. An inch is about the most for the seeds of the best-equipped insects in our parts. Now the newborn Decticus, hopping awkwardly in the grass at the approach of summer, is, like the adult, endowed with a pair of very long tentacles, vying with hairs for slenderness; he carries behind him two extraordinary legs, two enormous hinged levers, a pair of jumping-stilts that would be very inconvenient for ordinary walking. How does the feeble little creature set to work, with this cumbrous luggage, to emerge from the earth? By what artifice does it manage to clear a passage through the rough soil? With its antennary plumes, which an atom of sand can break, with its immense shanks, which the least effort is enough to [[242]]disjoint, the mite is obviously incapable of reaching the surface and freeing itself.
The miner going underground puts on a protective dress. The little Grasshopper also, making a hole in the earth in the opposite direction, must don an overall for emerging from the earth; he must possess a simpler, more compact transition-form, which enables him to come out through the sand, a delivery-shape analogous to that which the Cicada and the Praying Mantis use at the moment of issuing, one from his twig, the other from the labyrinth of his nest.
Reality and logic here agree. The Decticus, in point of fact, does not leave the egg in the form in which I see him, the day after his birth, hopping on the lawn; he possesses a temporary structure better-suited to the difficulties of the emergence. Coloured a delicate flesh-white, the tiny creature is cased in a scabbard which keeps the six legs flattened against the abdomen, stretching backwards, inert. In order to slip more easily under the ground, he has his shanks tied up beside his body. The antennæ, those other irksome appendages, are motionless, pressed against the parcel.
The head is very much bent against the [[243]]chest. With its big, black ocular specks and its undecided and rather bloated mask, it suggests a diver’s helmet. The neck opens wide at the back and, with a slow throbbing, by turns swells and subsides. That is the motor. The new-born insect moves along with the aid of its occipital hernia. When uninflated, the fore-part pushes back the damp sand a little way and slips into it by digging a tiny pit; then, blown out, it becomes a knob, which moulds itself and finds a support in the depression obtained. Then the rear-end contracts; and this gives a step forward. Each thrust of the locomotive blister means nearly a millimetre[4] traversed.
It is pitiful to see this budding flesh, scarcely tinged with pink, knocking with its dropsical neck and ramming the rough soil. The animal glair, not yet quite hardened, struggles painfully with stone; and its efforts are so well directed that, in the space of a morning, a gallery opens, either straight or winding, an inch long and as wide as an average straw. In this way the harassed insect reaches the surface.
Half-caught in its exit-shaft, the disinterred one halts, waits for its strength to [[244]]return and then for the last time swells its occipital hernia as far as it will go and bursts the sheath that has protected it so far. The creature throws off its miner’s overall.