NATURAL SCIENCES OF PHILADELPHIA. 53 



the idea of constructing a tree of life, based upon the habits of 

 the Heterocera during their larval history, suggested itself to my 

 mind. After many hours of toil I have been enabled to construct 

 a tree which will, I hope, bear the scrutiny of investigation and 

 come out unscathed, since it harmonizes in the arrangement of its 

 parts with the most thorough system of classification. 



