vi. INTRODUCTION - 



with, which, besides its interest, is essential to the 

 proper understanding of the relationship among the 

 vast hordes of insect species extant, and to their 

 systematic grouping into orders, sub-orders, and 

 families, which are defined by the authors through- 

 out the book. Then the life histories of many 

 species have beer^; described and figured, which 

 revealing the development, metamorphoses, and the 

 behaviour of insects, proves of perennial interest to 

 students. 



Finally, in recalling the bionomics of leaf and 

 fruit-eating species, sap-sucking and wood-boring in- 

 sects, and the blood-sucking forms which affect 

 stock or man, the economic significance of insect 

 life becomes apparent. Apart from their interest, 

 the lives of both useful and injurious species Avill 

 take on a new importance in the minds of readers. 

 The adequate study of insects which occasion such 

 losses in our crops, orchards and gardens, which 

 affect stock, destroy stored products, or are con- 

 cerned in carrying disease, presents a huge and 

 varied field for research. This is the province of 

 Economic Entomology, and it is augmented by the 

 research and experiments necessary to arrive at 

 effective and yet economical methods of control, 

 whether by spraying, fumigation, modifying farm 

 practice, by the artificial encouragement of natural 

 parasitism, or whatever means may suggest itself 

 and prove effectual in preventing or controlling a 

 pest. Communities are now growing to realise the 

 increased production and immediate monetary sav- 

 ing which may result from such investigations by 



