# Insects, Their Ways and Means of Living/Preface

PREFACE
In the early days of zoology there were naturalists who spent much time out of doors observing the ways of the birds, the insects, and the other creatures of the fields and woods. These men were not steeped in technical learning. Nature was a source of inspiration and a delight to them; her manifestations were to be taken for granted and not questioned too closely. A mind able to accept appearances for truth can express itself in the words of everyday language—for language was invented long ago when people did not bother themselves much with facts—and some of those early writers, inspired direct from nature, have left us a delightful literature based on their observations and reflections on the things of nature. The public has liked to read the works of these men because they tell of interesting things in an interesting way and in words that can be understood.
At the same time there was another class of nature students who did not care particularly what an animal did, but who wanted to know how it was made. The devotees of this cult looked at things through microscopes; they dissected all kinds of creatures in order to learn their construction and their structural relationships. But they found many things on the inside of animais that had never been named, so for these things they invented names; and when their books were printed the public could not read them because of the strange words they contained. Moreover, since nature does not usually embellish her hidden works, the anatomists could not enhance their writings with descriptive metaphors in the way the outdoor naturalists could. Consequently, the students of structure have never come into favor with the reading public, and their works are denounced as dry and tedious. ​Then there arose still another group of inquiring minds. Members of this school could not see anything worth while in knowing merely either what an animal did or how it was made. They devoted their efforts to discovering the secrets of its workings. They invented instruments for measuring the power of its muscles, for testing the nature of the force that resides in its nerves; they made analyses of its food and its tissues; they devised all kinds of experiments for revealing the causes of its behavior. The workers in this branch, the physiologists, had to have a considerable grounding in physics and chemistry; consequently they came to write more or less in the languages of those sciences and to express themselves in chemical and mathematical formulae. Their writings are hard for the public to understand. Their statements, moreover, are often at odds with preconceived ideas, since preconceived ideas are conceived in ignorance, and the public at large does not take to this sort of thing—it cherishes above all its inherited opinions.
Therefore the old-time naturalist is still venerated, as he deserves to be, and those who call themselves "nature lovers" still like to decry the laboratory worker as an evil being who would take the beauty from nature and destroy the soul of man. A modern writer of the old school may sell his wares, but when something goes wrong with his stomach or his nerves, or when his plants or his animals are attacked by disease, it is the knowledge of the laboratory scientist that comes to his aid.
The reason that the specific truths of nature must be found out in laboratories is that there are too many things mixed together in the fields. The laboratory naturalist endeavors to untangle the confusion of elements in the outdoor environment and to isolate the different factors that affect the life and behavior of an animal, in order that he may be sure with just what he is dealing in his efforts to determine the value of each one separately. By creating a set of artificial environments in each of which ​only one natural factor is allowed to be operative at the same time, he is in a position to observe correctly, after repeated experiments, just what effects proceed from this cause and what from that.
Nature study, in the superficial sense, may be entertaining. We of the present age, however, must learn to take a deeper insight into the lives of the other living things about us. Insects, for example, are not curiosities; they are creatures in common with ourselves bound by the laws of the physical universe, which laws decree that everything alive must live by observing the same elemental principles that make life possible. It is only in the ways and means by which we comply with the conditions laid down by physical nature that we differ.
Many sincere people find it difficult to believe in evolution. Their difficulty arises largely from the fact that they look to the differences in structure between the diverse types of living things and do not see the unity in function that underlies all physical forms of life. Consequently they do not understand that evolution means the progressive structural divergence of the various life forms from one another, resulting from the different ways that each has adopted and perfected for accomplishing the same ends. Man and the insects represent the extremities of two most divergent lines of animal evolution, and by reason of the very disparity in structure between us the bond of unity in function becomes all the more apparent. A study of insects, therefore, will help us the better to understand ourselves in so far as it helps us to grasp the fundamental principles of life.
Some writers seem to think that the sole purpose of writing is that it shall be read. Just as reasonable would it be to claim that the only purpose of food is that it shall be eaten. In the following chapters the reader is offered an entomological menu in which the consideration of nutrient value and the requirements of a balanced meal have been given first attention. As a concession to ​palatability, however, as much as possible of the distasteful matter of technical terminology has been extracted, and an attempt has been made to avoid the pure scientific style of literary cuisine, which forbids the use of all those ingredients whose object is that of inflation but which, if properly admixed, will greatly aid in the process of digestion.
Much of the material in several chapters is taken from articles already printed in the Annual Reports of the Smithsonian Institution. The original drawings of most of the color plates and line cuts are the property of the United States Bureau of Entomology, though some of them are here published for the first time.