ADTERTISEMENT. 



The present work is one of a series published by the Smith- 

 sonian Institution for tlie purpose of facilitating the study of 

 certain branches of the Natural History of North America wliich 

 appear to require special aid. It has been prepared, at the 

 request of the Institution, by Dr. LeConte and Dr. Horn. 



SPENCER F. BAIRD, 



Secrelary S. I. 



Smithsonian Institution, 



Washington, Febi-uary, 1883. 



PHILADELPHIA: 

 COLLINS, PRINTER. 



