This little volume mainly consists of a reprint of a series of essays which appeared in the "American Naturalist" (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 Insects." 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 whatever 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 organized 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 seems absurd to many. To another generation of naturalists it must, perhaps, be left to decide whether to attempt the one is more unphilosophical than to attempt the other.

Most of the cuts have already appeared in the "Guide to the Study of Insects" and the "American Naturalist," where their original sources are given, while a few have been kindly contributed by Prof. A. E. Verrill, the Boston Society of Natural History, and Prof. C. V. Riley, and three are original.

Salem, June, 1873.