Others toil underground. The innocent lobworm, which pierces and stirs up the soil, gets ready in a marvellously excellent manner the muddy and clayey earths which are deficient in evaporation. Others, in company with the mole, hunt far down in the depths the cruel enemy of agriculture, the horribly voracious larva of the destructive cockchafer, which, for three years, has been preying on the roots beneath the surface.
The insectivorous insects put forth undeniable claims to the protection of man, whose allies they are. But even among the herbivora there are useful destroyers of harmful plants. The useless, pungent, and in every sense disagreeable nettle, which scarcely a single quadruped will deign to touch, fifty species of insects, in fellowship with ourselves, labour to destroy.
A very beautiful class of insects, some rich in outward garb, and others in intelligence, are the Necrophori, which render us the important service of clearing away all dead matter from the soil. Nature, which finds them so useful, has treated them truly as her favourites, honouring them with splendid costumes, and making them both industrious and ingenious in the discharge of their functions. It is a remarkable circumstance that, notwithstanding their sinister office, they are far from being wild, but are very sociable if the need arises, and understand how to unite their forces, combine their energies, and act in concert. In brief,—these honest undertakers and grave-diggers are the brilliant aristocracy of the insect nation.
It is evident that Nature's ideas are not the same as ours. She loads the most useful with rewards, whatever the nature of their work. For instance, the Geotrupes, which clears away the dung, is clothed in sapphire in payment of its service. The celebrated Coleopteron of Egypt, the sacred Ateuchus of the tombs,[J] appears glorified with an emerald aureola.
[J] The Ateuchus sacer, or Sacred Scarabæus of the Egyptians.
Who shall describe all the services rendered by these scavengers? Yet we are not just in our dealings with them. It happened to me, one April, when I was about to transplant to my garden some dahlias which had passed the winter in the orchard, to discover that the humidity of the air of Nantes, and the compact and imporous clayey soil, had rotted the tubers. A bevy of insects were at work upon them, and usefully engaged in purging this shocking centre of dissolution. The gardener was very indignant, and ready enough to accuse them of the evil which they were endeavouring to remedy.
The enemy of damp gardens, the snail (Helix), is pursued by an insect,[K] the Drylus, which lies in wait for it, and, the better to hunt it up, mounts on its back, and makes it carry him, seizes a favourable opportunity, and on the snail re-entering its shell, enters also, lives with it and upon it. A snail lasts him about a fortnight. Then he passes on to another and a larger, and then to a third still larger. He requires three in all. In the third, as he is about to change into a pupa, the drylus makes the place clean, and, to sleep conveniently, seizes on the substantial house of the enemy which has nourished him.
[K] The larva of the Drylus flavescens.