ADVERTISEMENT 
THE SIXTH EDITION, 
Wuen the present work was originally published, the Authors 
had no expectation that the demand for it would be so extensive 
and permanent as it has proved; and they need not say how grati- 
fying this unlooked-for result has been to their feelings, as realising 
their earnest hope of assisting to remove the prejudices against 
the study of Entomology, which existed in full force thirty years 
ago when they took up the subject, but which have now happily 
disappeared. 
Though, however, a regular annual demand for a certain num~ 
ber of copies has always continued up to the present time, so as 
to have exhausted the last edition, the publishers have suggested 
that the future sale of the work, and its main object — that of 
extending the knowledge of inseets—would be much forwarded, if 
the first two volumes, treating of their manners and economy, were 
published separately, so as to obviate the necessity to those who 
do not care to pursue the study farther, of being burdened with 
the heavy cost of two additional volumes of matter, chiefly tech- 
nical, in which they feel no interest, 
