Plenty of them may be found under stones in damp spots, under bark, and in similar localities, though they are often found in houses, and have frequently traversed the paper on which I have been writing this book. Cellars are favourite localities of theirs, and a little flour sprinkled on a plate or piece of paper in a cellar is tolerably sure to attract them. Although they are certainly not more than the fifteenth of an inch in length, they may be at once recognised by their peculiar attitude, which very much resembles that of a dog or cat in its usual sitting posture. As long as they are not disturbed they crawl about in a quiet manner, but if touched, or even alarmed, they suddenly make a tremendous leap, propelling themselves by means of a forked and elastic tail, doubled under their bodies, and acting just like the tongue of a Skip-jack. * * * * * BELOW the Skip-jack Beetle is shown the common Grasshopper, as an example of muscular leaping springs. We all know what wonderful leaps the Grasshopper, Cricket, and all their kin can make, the leaping movement being evidently intended more as a means of defence than as an ordinary mode of locomotion. The same may be observed in the Kangaroos and Gerboas, which are content to use an ordinary walking pace when undisturbed, but when alarmed can make tremendous leaps, and outstrip almost any pursuer. Even in Man, the Horse, the Dog, &c., which are most essentially leaping animals, the same principle is employed, the legs being used as muscular springs acted upon by the will of the owner. USEFUL ARTS. CHAPTER VII. FOOD AND COMFORT. Parents and their Young.--Milk, and the various Ways of obtaining and using it.--The Kafir Tribes and Clotted Milk.--The Tonga Islanders.--The Tartars.--Ants and Aphides.--Honey-dew.--Milch Cows in Insect-land.--Fish-tanks and Aquaria.--Bill of the Pelican.--Eggs and Chickens.--The Hen-coop.--Nest of Termite.--Workers and Queen.--Egg-hatching.--The Hen and her Young.--Artificial Egg-hatching Machine.--The Snake and her Eggs.--The Gad-fly and Bot-fly.--Preservation of Provisions.--Hanging Meat.--Eggs of the Lace-wing Fly.--Spider-eggs.--The Butcher’s Hook and the Claws of the Sloth.--Bats and Insects. This subject is necessarily a very large one, and I shall, in consequence, be obliged to compress it, though it might well make a separate work by itself. For Food represents the very existence of Man, considered as one of the animal world; and Comfort represents the progress of civilisation, by which man leaves day by day his savage and solitary nature behind him, and becomes social, moral, and elevated. * * * * *