ADVERTISEMENT.

THE present work is one of a series to be published by the Smithsonian Institution for the purpose of facilitating the study of certain branches of the Natural History of North America which appear to require special aid. It has been prepared, at the request of the Institution, by Dr. LeConte, to whom science is much indebted for thus devoting his time to the preparation of an elementary book, intended to introduce others to a field in which he has himself been so successful a pioneer.

JOSEPH HENRY,
Secretary S. I.

SMITHSONIAN INSTITUTION,

WASHINGTON, May, 1861.

The preceding advertisement was written and published with page 1-208, in May, 1861. Since then, pages 209-278, completing Part I of the present work, have been prepared and are now published.

The second and concluding part of the work will contain the families embraced in the divisions Tetramera and Trimera of the older authors. Some time will, however, necessarily elapse before it can be prepared by Dr. LeConte.

February, 1862.

J. H.

ACCEPTED FOR PUBLICATION, OCTOBER, 1860.

PHILADELPHIA:

COLLINS, PRINTER.

PREFACE.

THE science of Entomology, in this country, is to a very considerable degree traditional. The series of specimens which are arranged and named have assumed their scientific value entirely from the labors of four or five individuals, who, from peculiarly favorable circumstances, have been enabled to lay a groundwork for scientific investigation by conference or correspondence with European students.

The present small treatise, prepared at the request of the Smithsonian Institution, is intended, so far as relates to the determination of genera of Coleoptera, to obviate the necessity for this traditional knowledge, and to enable those who have a desire beyond that of the mere collection of specimens to acquire sufficient information to enable them to consult with profit the various works in which are found scattered the descriptions of our species.

At the same time it is designed to present in as compact a form as possible the most recent results of scientific analysis, as applied to the classification of those genera of Coleoptera which have been found in that portion of America north of Mexico. In presenting these results, I have by no means adhered to the opinions expressed by those who have previously written on the classification of the order of insects which will occupy our attention; but where it has seemed to me possible to change with advantage the schemes already proposed, I have not hesitated to alter them.

The work is, therefore, intended for two classes of persons— for those who wish to obtain a knowledge of this branch of science, and for those who have already acquired that knowledge, and who now occupy the position of investigators.

The first class, or beginners, will here find the elementary

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results obtained from a long course of reading and the observation of abundant materials. A knowledge of these results will enable them to understand the more special memoirs which they will find it necessary to use in the prosecution of their future studies, and eventually to correct any errors which are contained in the present treatise. The second class, or investigators, will find herein certain views proposed for their adoption, which, with the material afforded by our fauna, seem to the author to be preferable to those presented in previous works. Many of the presumed improvements will no doubt be rejected, but it is hoped that at all events they will help, like those which have gone before them, to establish a basis for future progress.

Bibliographical references have been avoided in the body of the work; they would increase considerably the size, without rendering the work more useful. The beginner does not need them; the investigator knows where to find them in more general works.

I have derived great aid in the preparation of this work from the Genera des Coléoptères, by my learned friend Prof. Th. Lacordaire, and from the Genera des Coléoptères d'Europe, by Jacquelin du Val, both admirable works, which, except in some very intricate cases, render any reference to the earlier authors on the subject of genera almost unnecessary.

In conclusion, I would repeat that the present work is not expected to inspire any one with a love for this branch of Entomology, but to satisfy, so far as I am able, the desires which have arisen in the minds of those in whom the sacred fire of science has already been kindled.

PHILADELPHIA, April, 1861.

JOHN L. LECONTE.