PREFACE. 



THE issue of this volume completes the monograph 

 of the Coccidse of the British Isles. As my investiga- 

 tions have extended over a period of nearly fourteen 

 years it may reasonably be assumed that the work is 

 thoroughly representative of the coccid fauna of this 

 country ; but owing to the rapid means of transit it is 

 highly probable that aliens may from time to time 

 arrive here on freshly-imported plants. 



The introductory chapters given in vol. i on the life- 

 history and metamorphoses of the Coccidse have been 

 largely supplemented in this volume by many new 

 and interesting observations ; the most noteworthy 

 will be found at pp. 58-66, 130, 135, 180, 218-220. 



The number of species found within the British 

 Isles is eighty-eight, with four varieties ; of this total, 

 fifty-one species and two varieties have been found 

 living under glass, and have undoubtedly been intro- 

 duced from other countries. A few of these aliens 

 have, apparently, existed in this country as plant pests 

 for more than half a century ; while others have been 

 introduced within the last fifteen years, and, with the 

 exception of a few species, have apparently come to 

 stay and add to the difficulties of plant-culture. 



During the progress of the publication of this work 

 several important changes in the nomenclature of the 

 Coccidae have been suggested by other students of the 

 group, which if adopted will involve a remarkable 

 interchange of several long-established generic names. 

 Thus, in order to accord with the laws of priority, it 



