The subject of this paper was selected with enthusiasm. The law of natural compensations seemed most intriguing and the part played by forest insects in its enforcement appeared to afford unusual opportunity for discussion. Now that the time has arrived for its presentation there is a sense of trepidation, because the drawing of generalizations is always dangerous. However, without generalizations we should inevitably be confused by the mass of information concerning populations of insects, their parasites, predators, and host plants, and the responses of these organisms to their habitat. Therefore, it may be appropriate to present this somewhat old story from a different angle to illustrate the viewpoint of one forest entomologist, using some old and some hitherto unreported examples. Most of the examples that will be cited, whether old or new, have been observed first hand.