viii PREFACE TO THE FIRST EDITION 



body of more advanced workers interested in its general problems. 

 Some approach the subject from the standpoint of unfettered 

 research ; many others are practical entomologists whose occupa- 

 tion is largely directed towards insect control ; and there are those 

 who teach entomology and whose outlook requires them to com- 

 bine those of the others just mentioned. If this volume fulfils 

 their several requirements, to the extent that they derive some 

 profit by reading it, the author will feel amply repaid. 



Opportunity is taken here of expressing indebtedness to 

 Dr. F. Muir for reading and criticising parts of the book when in 

 manuscript, and to all those whose writings have been drawn 

 upon in preparing it. M. d'Emmerez de Charmoy has kindly sup- 

 plied information with respect to biological control measures 

 in Mauritius. Dr. Anton Handlirsch has generously consented to 

 the use of several illustrations contained in his article " Ueber 

 die fossilen Insekten," published in the Proceedings of the First 

 International Entomological Congress. Mr. Arthur Gibson, 

 Dominion Entomologist for Canada, has loaned several original 

 drawings pertaining to publications issued by his Division. Dr. 

 R. J. Tillyard has also granted permission to use several illustra- 

 tions from his papers. Indebtedness is also expressed to Sir Guy 

 Marshall for the use of Fig. 94, which is taken from the Bulletin of 

 Entomological Research ; to Mr. Clyde W. Mason for three figures 

 taken from his articles dealing with structural colours in insects ; 

 to Dr. R. E. Snodgrass and Dr. H. E. Ewing for the use of several 

 illustrations taken from their respective publications issued by the 

 Smithsonian Institution. Thanks are also due to the latter body 

 for its consent to their adoption. A number of other figures have 

 been borrowed, or adapted, from various sources and acknow- 

 ledgments are made to the authors concerned in the respective 

 legends. 



A. D. IMMS. 



July, 1930. 



