PRINCIPLES 



ECONOMIC ZOOLOGY 



BY 



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



PROFESSOl! OF ZOOLOGY, STATE NORMAL SCHOOL, KIKKSVILLE, MO. 



AND 



M. C. DAUGHERTY 



AUTHOR WITH JACKSON OF "AGRICULTURE THROUGH THE LABORATOI 

 AND SCHOOL GARDEN " 



SECOND EDITION. REVISED 

 WITH 301 ILLUSTRATIONS 



PHILADELPHIA AND LONDON 



W. B. SAUNDERS COMPANY 



1917 



