“I suppose that every man thinks his own line is the best, but I tell you, my boy, I’ve never found anything one-half so interesting as the piecing together, bit by bit, bone by bone, of a life that was lived a million years ago, on a world on which no human eye has ever looked. Books of travel will give you pictures, Perry, of things that there are in this world only a few hours’ or a few days’ journey away, but the books of travel that you and I are reading, my boy, will give pictures of scenes that no railway train can reach, and will reveal oceans that no steamship or sailing craft can cross.” That evening when they were sitting around the tent, vainly trying to keep away the flies that buzzed perpetually around their heads, Perry asked suddenly: “Uncle George, how far back in geology did flies begin?” “Carboniferous Period,” the professor answered. “We find their wings in the seams of coal, but probably early forms lived long before that. Those flies, however, belonged to the group that have an imperfect metamorphosis, such as the dragon-flies and cockroaches. Cockroaches, you know, Perry, are very ancient. But the house-fly, the kind that seems to be annoying you, my boy, isn’t so very old, certainly not much before the middle of the Age of Reptiles.” “I wish their teeth or feet or something hadn’t developed properly,” the boy replied savagely, swatting at one that persisted in trying to settle on his nose. “Something ought to happen to make them die out.” “Not much chance, I’m afraid,” the scientist responded wearily, “the fly isn’t particularly likely to die out soon. He squats on a baking rock in the equator and he perches on an ice-floe in the Arctic Circle. There’s not an inhabited island—no matter how far from all other land, that hasn’t got some kind of a fly on it. He’s been on the job for fourteen million years, and there are over two hundred thousand different species of fly still. I believe that when the last man lies down for his last sleep on some summer evening, there will be a fly buzzing around to settle on his nose.” “One wouldn’t think there was much attraction to bring flies out to this desert place,” put in Perry, “but they’re like a plague here now.” “Flies were one of the ten plagues of Egypt, weren’t they,” suggested Antoine, “and I suppose they will plague Egypt to the end of time.” “There are no mosquitoes here, at least,” Perry’s uncle reminded him, “not unless you bring some up from Birket-el-Qurun. There are plenty of them around the lake. But as long as the only water we get is what is carried here in fantasses by the camels, we’re safe from mosquitoes, because, as you know, those pesky little insects have got to have stagnant water in which to breed.” “I’d almost be willing to swap this swarm of flies for a few mosquitoes,” declared the boy, waving his arms around him frantically. “They’re in the sleeping-tent; they’re everywhere.”