I 
ii 
issued every three months. Figures of both surfaces will be given, and of both 
sexes wherever possible. The pages will not be numbered, but, with the plates, 
will be so arranged that finally the species of each genus can be brought together. 
This plan admits any enlargement of the volume which, whenever concluded, will 
be complete in itself. 
By North America is to be understood all that j>art of the Continent north of 
Mexico, according to the division adopted by the Smithsonian Institution. 
The letter press will, in most cases, necessarily be confined to technical descrip- 
tions, but whenever it is possible, such a history of the species will be given as I 
have been able to gather from my own observations or from others. 
It is a matter of regret that, in so few instances, I shall be able to say any- 
thing of the larvae. Even among our old and common species, the larvae are but 
little more known than in the days of Abbot, seventy years ago. His observations 
seem to have been more thorough or more fortunate than those of any of his 
successors. 
With the second or third number a Synopsis of Species will be commenced, 
and will be concluded within the volume. 
Philadelphia, March, 1868. 
W. H. EDWARDS. 
