INTRODUCTION AND ACKNOWLEDGMENT. 



There have always been repeated requests at this office for publica- 

 tions on California insects, suitable for use by the orchardist and horti- 

 cultural inspector. To meet these demands Mr. 0. E. Bremner, then 

 secretary of the State Commission of Horticulture, issued a bulletin on 

 "Destructive Insects and Their Control" in the year 1910. That the 

 work was popular is shown by the fact that the large supply printed has 

 l)een entirely exhausted for nearly a year and with urgent requests con- 

 tinuing to arrive at the office for a similar treatise. The present bulletin 

 has been printed to meet these demands. 



It has been the aim to make this issue as clear, concise and practical 

 as possible. Only insects of the most economic importance known to 

 occur in California are considered, so this is in no wise a work on general 

 entomology, and such limitations will better enable an orchardist or 

 horticultural official to get a more thorough grasp of the field of insect 

 life as it actually exists in this State. 



Much of the information contained herein has been compiled from 

 entomological publications of the State University, the many state ex- 

 periment stations, Bureau of Entomology of the United States Depart- 

 ment of Agriculture, and of private authors. 



The cuts alreadj^ in the office have been used for illustrative purposes 

 as far as available. Most of these are reproductions from publications 

 of the United States Department of Agriculture. The State University 

 has also loaned us a generous supply. The author's illustrations for- 

 merly used in the Pomona College Journal of Entomology have also 

 been procured, while many new cuts appear herein for the first time. 



E. 0. ESSIG. 

 Sacramento, California. 

 January 1, 1913. 



