PREFACE. 



THIS little volume mainly consists of a reprint of a 

 series of essays which appeared in the "American Natu- 

 ralist" (Vols. i-v, 1867-71). It is hoped that their 

 perusal may lead to a better acquaintance with the 

 habits and forms of our more common insects. The 

 introduction was written expressly for this book, as 

 well as Chapter XIII, "Hints on the Ancestry of In- 

 sects." The scientific reader may be drawn with greater 

 interest to this chapter than to any other portion of 

 the book. In this discussion of a perhaps abstruse 

 and difficult theme, his indulgence is sought for what- 

 ever imperfections or deficiencies may appear. Our 

 systems of classification may at least be tested by the 

 application of the theory of evolution. The natural 

 system, if we mistake not, is the genealogy of organ- 

 ized forms ; when we can trace the latter, we establish 

 the former. Considering how much naturalists differ 

 in their views as to what is a natural classification, it 

 is not strange that a genealogy of animals or plants 



