The Hairy Ammophila, therefore, feeds her grubs on the caterpillars of Noctuæ; and her choice falls exclusively on the species that live underground. These caterpillars, commonly known as Grey Worms, because of their drab garb, are a most formidable scourge to agricultural crops, as well as to garden produce. Curled in their burrows by day, they climb to the surface at night and gnaw the base or collar of the herbaceous plants. Everything suits them: ornamental plants and edible plants alike. Flower-beds, market-gardens, fields are laid waste without distinction. When a seedling withers without apparent cause, draw it to you gently; and the dying plant will come up, but maimed, severed from its root. The Grey Worm has passed that way in the night; its greedy mandibles have performed the deadly amputation. Its havoc rivals that wrought by the White Worm, the grub of the Cockchafer. When it swarms in a beet-country, the damage amounts to millions. This is the terrible enemy against which the Ammophila comes to our aid. I point out and urgently recommend to agriculturalists this valuable auxiliary, so zealous in her search of the Grey Worm in spring, so skilful in discovering its hiding-place. An Ammophila in a garden may mean the saving of a lettuce-bed, the snatching of a balsam-border from danger. But there is need here for recommendations. None would dream of destroying the pretty Wasp that goes fluttering nimbly from one path to the other, that visits this corner of the garden, then that, then the next, then the one over there; none dreams either—and none, unfortunately, can dream—of assisting her to multiply. In the immense majority of cases the insect evades our influence: to exterminate it, if it be harmful, to propagate it, if it be useful, are impracticable undertakings for us. By a singular contrast of strength and weakness, man cuts through the neck of continents to join two seas, he pierces the Alps, he weighs the sun; and yet he cannot prevent a wretched maggot from enjoying his cherries before he himself does, nor an odious Louse from destroying his vines! The Titan is vanquished by the pigmy. Now we have here, in this insect-world, an auxiliary of high merit, the supreme foe of our grievous foe the Grey Worm. Can we do anything to stock our fields and gardens with it at will? We cannot; for the first condition of multiplying the Ammophila would be to multiply the Grey Worm, the only food of her family of grubs. I do not speak of the insurmountable difficulties which this breeding would present. We have not to do with the Bee, who is faithful to her hive, because of her social habits; still less with the stupid Silkworm, perched on its mulberry-leaf, or its clumsy Moth, who for a moment flutters her wings, pairs, lays her eggs and dies: we have to do with an insect that is capricious in its wanderings, swift of flight and independent in its ways.