The same applies to the Locusts. They have no industry of their own specially devised [[395]]for laying eggs in strata in a keg of froth and extending this keg into an ascending-shaft. The mother, with her abdomen plunged into the sand, expels at the same time eggs and foamy glair. The whole becomes coordinated of its own accord simply by the mechanism of the organs: on the outside, the frothy material, which coagulates and becomes encrusted with a bulwark of earth; in the centre and at the bottom, the eggs arranged in regular strata; at the upper end, a column of yielding foam.
The Tryxalis and the Grey Locust are early hatchers. The latter’s family are already hopping on the yellow patches of grass in August; before October is out, we are frequently coming across young larvæ with pointed skulls. But in most of the other Acridians the ovigerous sheaths last through the winter and do not open until the fine weather returns. They are buried at no great depth in a soil which is at first loose and dusty and which would not be likely to interfere with the emergence of the young larvæ if it remained as it is; but the winter rains cake it together and turn it into a hard ceiling. Suppose that the hatching takes place only a couple of inches down: how is [[396]]this crust to be broken, how is the larva to come up from below? The mother’s unconscious art has provided for that.
The Locust at his birth finds above him, not rough sand and hardened earth, but a perpendicular tunnel whose solid walls keep all difficulties at a distance, a road protected by a little easily-penetrated foam, an ascending-shaft, in short, which brings the new-born larva quite close to the surface. Here a finger’s-breadth of serious obstacle remains to be overcome.
The greater part of the emergence therefore is accomplished without effort, thanks to the terminal appendage of the egg-barrel. If, in my desire to follow the underground work of the exodus, I experiment in glass tubes, almost all the new-born larvæ die, exhausted with fatigue, under an inch of earth, when I do away with the liberating appendage to the shells. They duly come to light if I leave the nest in its integral condition, with the ascending-shaft pointing upwards. Though a mechanical product of the organism, created without any effort of the creature’s intelligence, the Locust’s edifice, we must confess, is singularly well thought out. [[397]]
Having come quite close to the surface with the aid of his ascending-shaft, what does the young Locust do to complete his deliverance? He has still to pass through a layer of earth about a finger’s-breadth in thickness; and that is very hard work for budding flesh.
If we keep the egg-cases in glass tubes during the favourable period, the end of spring, we shall receive a reply to our question, provided that we have the requisite patience. The Blue-winged Locusts lend themselves best to my investigations. I find some of them busied with the work of liberation at the end of June.
The little Locust, on leaving his shell, is a whitish colour, clouded with light red. His progress is made by wormlike movements; and, so that it may be impeded as little as possible, he is hatched in the condition of a mummy, that is to say, clad, like the young Grasshoppers, in a temporary jacket, which keeps his antennæ, palpi and legs closely fixed to his breast and belly. The head itself is very much bent. The large hind-thighs are arranged side by side with the folded shanks, shapeless as yet, short and as it were crooked. On the way, the [[398]]legs are slightly released; the hind-legs are straightened out and afford a fulcrum for the sapping-work.
The boring-tool, a repetition of the Grasshoppers’, is at the neck. There is here a tumour that swells, subsides, throbs and strikes the obstacle with pistonlike regularity. A tiny and most tender cervical bladder engages in a struggle with quartz. At the sight of this capsule of glair striving to overcome the hardness of the mineral, I am seized with pity. I come to the unhappy creature’s assistance by slightly damping the layer to be passed through.
Despite my intervention, the task is so arduous that, in an hour, I see the indefatigable one make a progress of hardly a twenty-fifth of an inch. How you must labour, you poor little thing, how you must persevere with your throbbing head and writhing loins, before you can clear a passage for yourself through the thin layer which my kindly drop of water has softened for you!
The ineffectual efforts of the tiny mite tell us plainly that the emergence into the light of day is an enormous undertaking, in which, but for the aid of the exit-tunnel, the [[399]]mother’s work, the greater number would succumb.