6 PREFACE. 



voluine. On the return of Dr. Leach from the contuicnt ii> 

 May I consulted him on the subject, when he most hberally 

 promised me every assistance, with the free use of his books 

 raid 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. Avill pardon the oversight. 



To expei-ienced 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 lias 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 T-inn6 I have been obliged to give according 

 to my former plan, as the plates were engraved previous to the 

 alteration. The INIodem 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 Families terminating in ida. 



The introduction of Objects for the Microscope may "3" 

 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 



