PREFACE 



THE present volume is an attempt to present some of the 

 principles and practices of economic entomology in a form 

 that will illustrate the biological relationships of insects to 

 their environment. Like nearly all applied sciences, economic 

 entomology was early developed as an art, with little refer- 

 ence to biology, aiming toward the empirical application of 

 certain methods for the destruction or abatement of noxious 

 insects. 



The past few decades have witnessed great changes 

 whereby the field of the entomologist has been greatly ex- 

 tended, and he has been compelled, not unwillingly, to im- 

 prove his methods of investigation and to take advantage 

 of the rapid progress made not only in zoology and botany, 

 but in medicine and chemistry as well. He has naturally 

 greatly improved his efficiency, and has been enabled to in- 

 crease his usefulness to humanity many fold. 



The general public rarely appreciates fully the many 

 economic problems in relation to insects which continually 

 present themselves. Even the zoologist, be he morphologist, 

 ernbryologist, geneticist or student of animal behavior, often 

 regards the entomologist as a collector or cabinet naturalist, 

 who spends the greater part of his time impaling specimens 

 upon slender pins, and continually rearranging them in cork- 

 lined boxes. Unfortunately, this means toward an end seems 

 to be a bugbear from which the entomologist may never es- 

 cape, since he has to deal with a wonderfully varied and ex- 

 tensive series of animals. This very fact makes it difficult to 

 deal with insects in the brief and generalized manner applica- 

 ble to other groups of animals. As a consequence, entomo- 

 logical books and treatises naturally tend to assume ency- 

 clopaedic form. 



