VI. PREFACE. 



feel sure their interest will be aroused, and more extended 

 fields will be entered. And having gained some knowledge of 

 the Diptera, may I beg them not to stop short with mere 

 collecting, which after all is only a preliminary, but to go on 

 to the close and patient observation of the habits, and the 

 tracing out of the life histories. 



In addition to those mentioned in the Introduction, I desire 

 to thank Mr. Becker, of Liegnitz, for kindly examining some 

 species of Phora. And very specially do I thank Mr. E. 

 Leonard Gill for his most careful and painstaking correcting 

 of the typography, and for many valuable suggestions during 

 the course of publication. 



Bishop Auckland, 



16th April, 1906. 



