One of the commonest pursuits of boyhood is the formation of a collection of insects. The career of almost every naturalist of renown has been marked in its early stages by a propensity to collect these lower, yet most interesting and instructive, forms of animal life. Among the insects, because of their beauty, butterflies have always held a foremost place in the regard of the amateur collector. For the lack, however, of suitable instruction in the art of preserving specimens, and, above all, by reason of the almost entire lack of a convenient and well-illustrated manual, enabling the collector to identify, name, and properly classify the collections which he is making, much of the labor expended in this direction in the United States and Canada fails to accomplish more than the furnishing of temporary recreation. It is otherwise in Europe. Manuals, comprehensive in scope, and richly adorned with illustrations of the leading insect forms of Great Britain and the Continent, have been produced in great numbers in recent years in England, France, and Germany. The result is that the youthful collector enters the field in those countries in the possession of a vast advantage over his less fortunate American fellow. It is to meet this want on this side of the Atlantic that this volume has been written. Its aim is to guide the amateur collector in right paths and to prepare him by the intelligent accomplishment of his labors for the enjoyment of still wider and more difficult researches in this and allied fields of human knowledge. The work is confined to the fauna of the continent of North America north of the Rio Grande of Texas. It is essentially popular in its character. Those who seek a more technical treatment must resort to the writings of others. If I shall succeed in this book in creating a more wide-spread interest in the world of insect life and thereby diverting attention in a measure from the persecuted birds, which I love, but which are in many species threatened with extinction by the too eager attentions which they are receiving from young naturalists, who are going forth in increased numbers with shot-gun in hand, I think I shall render a good service to the country. I flatter myself that I have possessed peculiar facilities for the successful accomplishment of the undertaking I have proposed to myself, because of the possession of what is admitted to be undoubtedly the largest and most perfect collection of the butterflies of North America in existence, containing the types of W.H. Edwards, and many of those of other authors. I have also enjoyed access to all the other great collections of this country and Europe, and have had at my elbow the entire literature relating to the subject.