PREPACK. Vll 



and Prof. H. C. Fall, Pasadena. Cal.J for a very careful revision of 

 the Coleoptera; to Prof. J. M. Aldricn, United States Department of 

 Agriculture, for revising the Diptera; to Mr. W. M. Davidson also for 

 looking over the Syrphida ; ko Mr. Marry S. Smith also for revising 

 the Hymenopiera ; to Dr. jjOth" i -.. Dyar and Mr. August Busek, 

 United States National V 1 .'. J m and Mr. Fordyce Grinnell, Jr., Pasa- 

 dena, Cal., for devising I foptcra (the classification of Dr. Geo. 

 F. Hampson has been h illowed in the Lepidoptera, especially 

 in the Nochiidce) ; to Mr. '. Gray, University of California, for 

 revising the articles on spi i and fumigating: to Mr. Leroy Childs, 

 Oregon Agricultural College, for much assistance in gathering field 

 notes and material when he Avas assistant secretary of the Commis- 

 sion of Horticulture: to Mr. S U. Essig, horticultural inspector of 

 Ventura County and brother of the author, especially for the many 

 splendid specimens sent for illustrative purposes; to Miss Maude 

 Hiett, clerk of the State Commission of Horticulture, for assisting 

 in reading the manuscript and proof, and j . Nellie Mitchell 

 and Mrs. E. Stephens for their painstaking w'Vk in copying the 

 manuscript. 



Unless otherwise designated, the illustrations were either drawn 

 or photographed by the .author and u^d in previous writings or 

 here for the first time. 



The work was begun and largely finished Avhile the author was a 

 member of the State Commission of Horticulture, and, upon his 

 transfer to the University of California, arrangements were made 

 whereby he has been able to finish it with little or no interruption. 

 The generosity of the University authorities in this connection is 

 very greatly appreciated by the author and the State Commission 

 of Horticulture. 



E. 0. Essig. 



Berkeley, California, Mai/ 1, 1915. 



