Many noxious insects which used to live only in some one comparatively small region have been unintentionally transported by man to new environments where they have done immense damage. Amid wars and rumours of wars, while the acrimonies of disarmament conferences threaten the human race with unprecedented. The mammals, having become supreme, proceeded to grow big. Man, by his intelligence, has succeeded in finding nourishment for a large population, in spite of his size. But the biggest on land, the mammoth, is extinct, and the other large animals have grown rare, except man and those that he has domesticated. He is safe, except from the little creatures - the insects and the micro-organisms. Fortunately, science has discovered ways by which insects can be kept under. Most of them are liable to parasites which kill so many that the survivors cease to be a serious problem, and entomologists are engaged in studying and breeding such parasites.