4 PREFACE. 



tinguished from one another, and in species whicli resemble each 

 other so much as to render identification difficult, the cliaracter- 

 istic points of difference are put in itaHcs. 



In conclusion, I wish to express my sincere thanks to my 

 ornithological friends in general, for tlieir kind assistance, and 

 especially to Mr. George N. Lawrence, of New York, for much 

 valuable information. 



C. B. CORY. 



