PREFACE. 



-•o«- 



DURING 1863-4 a series of papers on the subject 

 of this work appeared in consecutive numbers 

 of the Popular Science Review. Partly on account 

 of their novelty (for nothing of the kind had before 

 been attempted^ of a popular character^ and in- 

 cluding so wide a scope) ^ and partly because every^ 

 one was more or less interested in these little pests 

 of the field and garden^ those papers were so 

 favourably received that the publisher has been 

 induced to re-produce them in a separate and col- 

 lected form. As far as I am personally concerned 

 I am glad that such an opportunity has been 

 afforded me of revising and expanding these 

 chapters, of which I have freely availed myself 

 in all directions. 



The results of more recent investigations, espe- 

 cially those of Dr. De Bary, have been embodied, 

 notices of species, since discovered in this country, 

 added, the number of illustrations nearly doubled. 



