PREFATORY NOTE 



The point of view from which this book is written is explained 

 in its first chapter. For that matter it is indicated clearly by 

 the title. If the study of zoology is being neglected in schools 

 for the alleged reason that it is not a useful study, the neglect 

 is based on an unsound reason. For zoology is useful, and not 

 in one way alone, but in two ways; and both of these in addition 

 to its pedagogic value as a study which develops accurate per- 

 sonal observation and independent personal attainment of 

 conclusion. 



Zoology is first of all useful in the way so often stressed by 

 Huxley, as a study that gives us a sounder basis for our own 

 life by showing the demands of Nature on animal life in general 

 and the kinds of responses to be made to these demands. In 

 other words it is quite specially a branch of science that can 

 help us largely as a guide to living in conformity to natural 

 laws. Zoology is also useful in a more obvious and commerci- 

 ally ratable way, by revealing the precise relation which many 

 animals bear to us in their attitude of friends to be cultivated, 

 or foes to be fought. Injurious insects, alone, cause this 

 country an annual loss of a billion dollars. A general knowl- 

 edge of insect life and an intelligent and vigorous application 

 of this knowledge can save the nation half this loss. 



To the teacher intending to use this book as class guide there 

 is due a word of explanation. The authors have attempted to 

 make the book an introduction to general zoology as well as 

 to that specific phase of it called economic. The first chapters 

 are therefore of a nature to introduce pupils to general facts of 

 animal structure and life. They are arranged on the basis of ac- 

 cepted pedagogic principles. The later chapters, arranged on 

 a basis of animal classification, proceeding from the simpler to 

 the more highly developed groups, include not only general facts 



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