PREFACE. 
6 
volume. On the return of Dr. Leach from the continent in 
May I consulted him on the subject, when he most liberally 
promised me every assistance, with the free use of his books 
and manuscripts, if I would extend the work. This was a 
kindness which I certainly did not expect, although I knew 
his zeal and ardour in the promotion of science : it was also 
an offer I could not withstand, and which no lover of science 
will regret. It has been my wish in no instance to omit ac- 
knowledging what has been derived from his valuable assist- 
ance : should this however have been in any case neglected, I 
trust that Dr. L. will pardon the oversight. 
To experienced scientific Entomologists this work cannot 
be expected to afford much additional information: their 
good sense will however admit its necessity and utility, since 
a publication on such a plan has long been a great deside- 
ratum ; yet even to these it is presumed it will not be altoge- 
ther useless, since it contains the characters of many genera 
lately established by the most celebrated Entomologists on 
the continent, and never before printed in this country. 
The Genera of Linud I have been obliged to give according 
to my former plan, as the plates were engraved previous to the 
alteration. The Modem System is nearly the same as that 
given in the Supplement to Encyclopaedia Britannica, article 
Crustaceology, and Dr. Brewster’s Edinburgh Encyclopaedia, 
article Entomology, with the exception of the foreign Genera 
and the alteration of Tribes to Eamilies terminating in id<z. 
The introduction of Objects for the Microscope may by 
some be considered as rather foreign to the subject of Ento- 
mology ; but this I cannot altogether accede to, since the as- 
sistance of this instrument is so often required, and many who 
possess a microscope might be induced to extend their views 
