268 THE COLONIZA TION OF NE W ENGLAND. 



diminished, and the differences more than pro- 

 portionally increased. 



It will be evident from what has been stated 

 that a considerable portion of the present butter- 

 fly fauna of the eastern United States has been 

 derived from the north, and a still greater portion 

 from the south. If we are to judge of the deriva- 

 tion of the present fauna by the geographical dis- 

 tribution of its nearest allies, we shall come to no 

 uncertain conclusions. Omitting from consider- 

 ation such species as belong properly to the ex- 

 treme north or south, and the few species believed 

 to have been introduced, there will be left about 

 one hundred and forty, which may be considered 

 the foundation of the fauna, including nearly 

 twenty genera peculiar to it. A careful study of 

 the affinities of these one hundred and forty 

 species shows that more than three-fourths of 

 both genera and species have their nearest allies 

 in the south, mostly in Mexico and Central 

 America. Nearly all of the remainder belong to 

 genera represented around the entire temperate 

 zone of the northern hemisphere. Excepting 

 those which are closely connected either with 

 European or with Western American species, I 

 do not recall a single genus peculiar to the region, 

 unless it be Feniseca, one of the Coppers, which 

 is unique. We may therefore conclude that our 

 fauna is in no respect endemic, and that by far 



