A barge transporting a large quantity of petroleum moves slowly down the middle of the Parana River in South America. Though it is early evening, the pilot is enclosed in torrid heat, fetid smells from the jungle's rotting vegetation, rampant palms that reach toward him on each side of the river, and the strange, floating beauty of blue and purple hyacinths, now swaying in his wake. The insect cries are deafening, louder than a New York subway. He does not pause to swat a mosquito, for there are none. Too small for this world, they have themselves been devoured by the far more populous insects half a foot long. Floating beside the barge are frogs larger than a small dog, the easy prey of jacares, another bloated amphibian that can outgrow a crocodile.