

PREFACE 



This volume requires very little preface, even though it has taken a long 

 time to produce. The delay has been partly caused by the abundance, 

 rather than the paucity, of literature upon the subject, as our British 

 species are very few in number as compared with those on the Continent, 

 while the common and more ancient species have, as a rule, been very 

 inadequately described. Very few of the British species can be considered 

 common, while many are exceedingly rare or local, and consequently 

 difficulties have arisen in obtaining specimens in first-class condition and 

 in identifying them. 



My special thanks are due to Col. J. W. Yerbury, who has not only 

 given me innumerable specimens which have been taken by him in recent 

 years, but who has criticised in detail every line of the " proofs " as the 

 work has been going through the press ; I may not have accepted all his 

 suggestions, but have done so in hundreds of cases. My thanks are also 

 due to Mr P. H. Grimshaw, who has also examined all the "proofs," and has 

 given valuable information as to localities, especially for Scotland. I hope 

 I have acknowledged other help in the body of the work. 



G. H. VEERALL. 



December 1908, 



