The eggs of this insect are deposited in the skin of the ox, and are there hatched by the heat of the animal. In proportion as the larva grows, it raises lumps upon the skin, these being practically the roofs of the artificial home. There are several other species of the same genus, all of which have their eggs hatched by the heat of the animals on which they are placed. There are, for example, the common Bot-fly (_Œstrus equi_), whose eggs are hatched in the interior of the horse, and the Sheep-fly (_Œstrus ovis_), whose eggs are hatched in the head of the sheep. The common Snake leaves her eggs to be hatched in the artificial heat produced by decaying vegetable matter. * * * * * WE now come to the preservation of provisions. In the first place, we have the well-known “cache” of Northern America--_i.e._ a spot wherein provisions are hidden, and their locality only marked by signs intelligible to those for whose use they are intended. It is, perhaps, hardly necessary to mention that many creatures--such as the dog, the squirrel, and most of the crow tribe--are in the habit of concealing provisions for future use. [Illustration: SPIDER-NESTS.] [Illustration: EGGS OF LACE-WING FLY.] [Illustration: SPIDER-NEST.] [Illustration: PROVISIONS HUNG TO TREE BRANCH.] In those parts of the world, however, where the rights of hunters are acknowledged, any one who kills a deer, or other animal of chase, and is not able to carry off the entire body, can preserve it for his own use. He simply cuts it up in hunter fashion, and hangs the various portions to branches of trees, where they are out of the reach of wild beasts. Stores like these, such as are shown in the illustration, are always respected, and no hunter would dream of helping himself to the game which was killed and dressed by another. Beasts of prey, however, cannot be expected to be so punctilious, and in consequence the hunters hang their meat to branches which cannot be reached. * * * * * IN Nature we find many similar examples, one or two of which are given on the left hand of the illustration. In the centre is seen a group of eggs of the Lace-wing Fly (_Hemerobius_), so called on account of the delicate, lace-like structure of its beautiful pale green wings. When the female lays her eggs she always chooses a slight twig, and upon it deposits a little drop of a slimy consistence. She then draws out this drop into a thread, which hardens as it is brought into contact with the air. At the extreme end of the thread she places an egg, which is thus kept at some height above the ground, and defies the approach of inimical insects. The eggs, as well as the stalks, are perfectly white, and have so singular a resemblance to mosses, that for many years they were actually classed and figured as such.