5. When a fly lights on a lump of sugar, it puts out its trunk, and lets fall a drop of fluid, which is clear like water. This moistens the sugar, and then the fly sucks it up.
A Fly's Leg,
magnified.
6. The fly keeps himself very clean. After each meal it brushes its head, first on one side, and then on the other, with its first pair of legs. Then it will rub the two legs together to get off the dirt.
7. The fly lays its eggs in the kind of food its young can eat. In a short time a little white grub hatches out, which does nothing but eat until it is of full size.
8. Then its skin becomes hard, and shrinks. It lies still, and does not eat anything for several days; but, inside its hard shell, wings are growing, and by-and-by the shell cracks open, and a full-grown fly comes out.
9. The blue-bottle fly has but two wings, while the common house-fly has four. This fly lays its eggs wherever it can find putrid meat, and the grubs which hatch out eat it all up, and so save us from evil odors and from breathing foul air.