[Footnote 33: Eighteenth Annual Report of the United States Geological Survey to the Secretary of the Interior, 1896-'97. Charles D. Walcott, Director. In Five Parts. Director's Report, including Triangulation and Spirit Leveling. Pp. 450, with 4 plates. Part II; Papers chiefly of a Theoretic Nature. Pp. 653, with 105 plates. Part III; Economic Geology. Pp. 861, with 118 plates. Part IV; Hydrography. Pp. 756, with 102 plates.] The purpose of _Belle S. Cragin's Our Insect Friends and Foes_[34] is illustrated from a passage in the author's own life, cited in the preface: "In my younger days, when Nature study was unknown in schools and my problems had to be solved by my own investigations or remain unsolved, I used to long for somebody to write a book that would tell me the things I wished to know, or show me how to find them out for myself; and that is what I have tried to do for you." The beginning of the book is a chapter on the collection, preservation, and care of insects for specimens, giving explicit directions for collecting them perfect, for putting them to death, for mounting and placing them in the cabinet, and for protecting them against vermin, dust, and mold, with descriptions of the instruments, cases, etc., that are used. In the descriptions of insects no attempt is made to mention any except the commonest species, and not all of those. The habitat, in most cases, is included in the description. As a rule, most of the species are those found in the States east of the Rocky Mountains and north of the Gulf States. Scientific names are attached to the illustrations and a list of popular names, with their scientific equivalents. The descriptions are brief and well adapted to the purpose indicated in the quotation with which our notice begins. [Footnote 34: Our Insect Friends and Foes. How to Collect, Preserve, and Study them. By Belle S. Cragin. New York: G. P. Putnam's Sons. Pp. 377. Price, $1.75.] In presenting a revision of their _Plane and Solid Geometry_[35] Messrs. _Beman_ and _Smith_ express their belief as being, that amid all the schemes for breaking away from the formal proofs of Euclid and Legendre and leading the student to independent discovery, the best results are secured by setting forth a minimum of formal proofs as models, and a maximum of unsolved or unproved propositions as exercises. They likewise share in the belief that such of the notions of modern geometry as materially simplify the ancient should find place in our elementary text-books. Accordingly, they have introduced various ideas, such as those of one-to-one correspondence, anti-parallels, negative magnitudes, general figures, prismatic space, similarity of point systems, etc., which are of real use in the early study of the science. In general, whatever is found to be usable in elementary work has been inserted where it will prove of most value.