issued everv three months. Figures of both surfaces vrill lie given, and of both 

 sexes wherever possible. The page.s 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 anv enlargement of the volume which, whenever concluded, will 

 be comjilete in itself. 



Bv Xortli America is to be understood all that part of the Continent north of 

 Mexico, according to the division adoj^ted 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 larva?. Even among our old and common species, the larvse 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 

 successor's. 



^^'ith the second or third numl)er a Synopsis of Sjiecies will be commenced, 

 and will be concluded within the volume. 



Philadelphia, March, 18(58. W. II. EDWARDS. 



