Spiracles
If you watch a grasshopper or a bee, you can plainly see it breathe. The abdomen moves in the bee as though it were panting. These movements of the abdomen cause the air to go in and out. All insects move their abdomens to send the air in and out, but it does not show plainly in all of them, for, though insects need air, some of them can get along with very little.
Yes, John, insects have blood. It is not just like our blood, but still it is blood.
It is not generally red in color, though sometimes it is reddish, and sometimes it is brown, or violet, or even bright green.
Yes, that seems strange to you, but you remember how ears are ears, and serve to hear with, no matter where on the body of the creature they are located. So blood is blood, and serves the purpose of blood, no matter what its color. The blood of some insects has a very bad odor, and in the case of certain beetles, when they are disturbed, this foul-smelling liquid oozes out of the joints of the legs.
Yes, Mabel, it is probably used, like the "molasses" of other little friends we know, to repel enemies.
But to return to breathing. Some larvæ breathe by gills, and do not have spiracles until they are grown up, but all grown-up insects breathe by spiracles.
Yes, John, the larvæ of the dragon flies and May flies breathe with gills.
I thought you would remember that.
The water boatman breathes by spiracles, and carries his supply of air with him. All grown-up bugs breathe by spiracles.