PRINCIPLES 



OF 



ECONOMIC ZOOLOGY 



. ' 



BY 



L S. DAUGHERTY, M.S., Ph.D. 



PROFESSOR OF ZOOLOGY, STATE NORMAL SCHOOL, KIRKSVILLE, MO. 



AND 



M. C. DAUGHERTY 



AUTHOR WITH JACKSON OF "AGRICULTURE THROUGH THE LABORATORV 

 AND SCHOOL GARDEN" 



WITH 301 ILLUSTRATIONS 



PHILADELPHIA AND LONDON 



W. B. SAUNDERS COMPANY o o N 



1912 



X 



