x PREFACE. 
characters much less difficult to examine, and also less 
liable to vary specifically. The correctness of this mode 
of distribution is proved by the correspondence of their 
general habit and of their economy. 
To make the book as complete as possible, for I con- 
sider every book should be as complete as is possible in 
itself, I have worked out the synonymy as fully as the 
materials in my possession would admit: in doing this, I 
have had occasion frequently to correct the inaccuracies 
and oversights of my predecessors; but I wish it to be 
fully understood, that this has been done solely for the 
sake of the science, and that it was never prompted by 
illiberal captiousness. My views of synonymy may pos- 
sibly differ from that of the majority ; for I cannot con- 
sider a mere citation as a synonym, having frequently 
detected, when a description was given, that the insect of 
the author referred to differed from that of the author 
writing. How is it therefore possible to ascertain the 
correctness of a reference, when nothing but the latter is 
given? I have, however, sometimes diverged from the 
strictness of this rule, when I had no doubt, arising from 
the collateral evidence of the invariable correctness of the 
author. The specific character I have moulded to my own 
occasions, it being necessarily variable according to the 
views pursued, and the specific descriptions have always 
been made from an autoptical examination of native spe- 
