monograph, which will, I hope, enable the student to form a rapid acquaintance with our ants, without recourse to the scattered and often very meager descriptions that have hitherto served as the taxonomy of the North American species.
I frankly admit that in writing the following pages I have endeavored to appeal to several classes of readers—to the general reader, who is always more or less interested in ants; to the zoölogist, who cannot afford to ignore their polymorphism or their symbiotic and parasitic relationships; to the entomologist, who should study the ants if only for the purpose of modifying his views on the limits of genera and species, and to the comparative psychologist, who is sure to find in them the most intricate instincts and the closest approach to intelligence among invertebrate animals. Of course, the desire to interest so many must result in a work containing much that will be dull or incomprehensible to one class of readers; thus the technical terms and descriptions, which are full of significance to the entomologist, are merely so much dead verbiage to the general reader, and the laboratory zoölogist, who shrinks at the mention of psychological matters, will care little about ant behavior beyond its physiological implications.
With the exception of the appendices and the first chapter, which serves as an introduction, my account of the ants falls naturally into two parts: a first, which is largely morphological, and comprises Chapters II to X; and a second, devoted to ethological considerations and embracing the remaining chapters. To some it may seem that too much space has been devoted to the relations of ants to other organisms and to other ants (Chapters XVI-XXVII), but I justify my procedure on the ground that this subject is the one in which I have been most interested, the one in which most advancement has been made within recent years, and the one that has been fraught with the greatest differences of interpretation.
The series of appendices has been added largely as an aid to the beginner in the study of myrmecology. The tables for the identification of our North American ants are very incomplete, but could not have been extended to embrace the species, subspecies and varieties, and the different castes, as well as the genera, without unduly increasing the size of the book. I hope to make good this defect in the monograph to which I have alluded. In the meantime, I shall be glad to identify ants for anyone who is interested in their study, especially if the specimens are collected in America north of Mexico. The identification of such material serves a double purpose: that of increasing our knowledge of the geographical distribution of our species, and of spreading throughout the country collections of correctly identified
