I believe that in the main insect surveys have been initiated each because of some definite need. In the case of surveys of pest species, such as the chinch bug, corn borer, or budworms, the need has been the necessity of obtaining accurate knowledge of population densities and areas of infestation, this to serve as a basis for predicting economic losses or extent of needed control operations.

In most instances general faunistic surveys have had a more roundabout motivation. This kind of a surrey usually starts out as an identification service, its aim to tell whether or not suspected insects are injurious or beneficial, and if injurious, how much so, and what is known regarding the control of the species. Here again the desire to predict is uppermost in our mind, as with the case of pest surveys. Difficulties always arise in distinguishing injurious from closely related non-injurious forms, or in being sure how many kinds of insects are involved in one groop or another. In attempting to solve these problems we gradually arrive at the point where we want to know how many kinds of all insects there are in a region, and how to tell them apart.