INTRODUCTION AND ACKNOWLEDGMENT.

There have always been repeated requests at this office for publications on California insects, suitable for use by the orchardist and horticultural inspector. To meet these demands Mr. O. 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 been entirely exhausted for nearly a year and with urgent requests continuing 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 experiment stations, Bureau of Entomology of the United States Department of Agriculture, and of private authors.

The cuts already 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 formerly used in the Pomona College Journal of Entomology have also been procured, while many new cuts appear herein for the first time. E. O. ESSIG.

Sacramento, California.

January 1, 1913.