Vin PEEFACE. 



America, and other memoirs, by Dr. Geo. H. Horn. But whenever a 

 general enumeration of the species in any group is given, without quali- 

 fication, it must be understood to embrace all the known North American 

 species. In stating the numbers of species, I have followed, for the most 

 part, the recently published Check List of Mr. G. E. Crotch, (1874). 

 Where two or more closely allied genera or sub-genera are merged in one, 

 all the species are, of course, included under the leading generic title. 

 A precise adjustment of species formed no part of my plan, and my 

 principal object in giving these numbers has been to show the compara- 

 tive numerical importance of the several families and their leading or 

 typical genera. 



In the definition of genera I have had constant reference to the great 

 work of Lacordaire on the genera of Coleoptera*; and to Dr. J. L. Le- 

 Conte's very accurate and scientific classification of the Coleoptera of 

 North America, prepared for the Smithsonian Institution. (Part 1st, 1 

 vol., 8 vo., 1861 ; and Part 2d, 1873.) To these elaborate systematic 

 works, and especially the latter, which, for obvious reasons, is most 

 readily available to the American student, the present treatise is only 

 intended to serve as an introduction or stepping stone; and to them the 

 reader is referred for more extensive details, and for the definition of 

 the smaller families and genera not included in the present work. 



In the families Chrysomelidse, Erotylidte, Eiidomychidte and Coccin- 

 ellidse, which have not been reached in either of the uncomideted works 

 just referred to, I have derived valuable aid from the synopsis of these 

 families by Mr. G. R. Crotch, recently published in the Proceedings of 

 the Academy of Natural Sciences of Philadelphia, and in the Transac- 

 tions of the American Entomological Society. 



I In treating of the internal structure of insects I have necessarily lim- 

 ited myself to the briefest general statements. Those who wish to pro- 

 secute further this department of the science, will find much interesting 

 matter in Dr. A. S. Packard's well known Guide to the study of In- 

 sects. 



It will be seen that some of the families of Coleoptera are much more 



fully treated than others. This has been owing, partly, to the greater 

 amount of material at my command, partly to the comparative impor- 

 tance of certain families in a practical or economic point of view, and 

 partly to the irregularity of the intervals at which the work has been 

 prosecuted, which has prevented that uniformity of execution which 

 would have been desirable. > 



In order to make this little work as useful as possible, I have added 

 a glossary of the terms most commonly used in descriptive entomology ; 

 and also, a brief catalogue of authors, especially those whose names ap- 



Genera dea Coleopteras. Ten vols. 8 to., Paris, 1854-1872. The author died before the completion 

 of this -work, and the tenth volume has not yet been published. 



