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An Introduction to Entomology. By John Henry Comstock. With many Original Illustrations, drawn and engraved by Anna Botsford Comstock. Part I. Ithaca, N. Y.: The Author. Price, $2.

Prof. Comstock designs that this work shall enable students to acquire a thorough knowledge of the elementary principles of entomology, and to classify insects by means of analytical keys similar to those used in botany. As the completion of the work has been delayed by other duties, the author has thought best to issue this part by itself. The first three chapters are of an introductory character. In Chapter I the general characters and metamorphoses of insects, which term the author restricts to the Hexapoda, are stated; Chapter II is a description of the anatomy of insects, fully illustrated; and Chapter III is devoted to the classification of the Hexapoda, The remaining chapters consist of descriptions of the more common or conspicuous species in each family, together with keys by means of which the student can readily determine to what family any insect of which he has a specimen belongs. In many cases tables of genera are also given. Much space has been devoted to accounts of the habits and transformations of the forms described. The needs of agricultural students especially having been kept in view, those species that are of economic importance have been described with considerable fullness. The rest of the work will be published as soon as practicable. In addition to the systematic part, in which four more orders—Lepidoptera, Diptera, Coleoptera, and Hymenoptera—remain to be described, there are to be chapters on the means of destroying insects or of preventing their ravages, on the collection and preservation of entomological specimens, on entomological supplies, a classified list of entomological works, a glossary, and an introductory chapter. This part comes in paper covers. It is well printed, and is abundantly illustrated.

Gleanings in Science: A Series of Popular Lectures on Scientific Subjects. By Gerald Molloy, D. D., D. Sc. London and New York: Macmillan & Co. Pp. 352. Price, $2.25.

With one exception, the lectures which make up this attractive volume were delivered before the Royal Dublin Society. In preparing them for publication the author has used whatever materials have come into existence since the lectures were delivered, so as to present the latest available information in each case. The subjects treated are included in the sciences of heat and electricity, except the Alpine glaciers, which are described in a lecture delivered to a young men's society. There are two lectures on the modern theory of heat as illustrated by the phenomena of latent heat, one of these dealing with the latent heat of liquids, the other with the latent heat of vapors. Lightning and thunder are treated in one lecture, lightning-conductors in another, and the storing of electrical energy in a third, while the recent controversy in England on lightning-conductors is sketched in an appendix. The electric light is the subject of two lectures; one telling how the electric current is produced, the other how the current is made to yield the light. Two lectures also are devoted to the sun as a store-house of energy: one describing the immensity of the sun's energy, the other discussing the theories as to its source. The treatments are thoroughly popular, avoiding mathematics and technical language, and, besides setting forth the present state of the science in each case, touch upon the history of the subjects and the practical applications of the principles stated. Descriptions of experiments are introduced, which the reader is helped to realize by many excellent illustrations. The lecture on "The Glaciers of the Alps" is especially fascinating, and owes part of its interest to the quotations and cuts borrowed from Mr. Whymper's "Scrambles among the Alps." The whole volume, in manner as well as in matter, reminds one of Tyndall's popular works, and will be found very attractive reading for any one who has an intelligent interest in science.

The Civilization of Sweden in Heathen Times. By Oscar Montelius, Ph. D. Translated by Rev. F. H. Woods, B. D. London and New York: Macmillan & Co. Pp. 214. Price, $4.

As in most countries, the archaeological chronology of Sweden embraces a stone, a bronze, and an iron age. The stone age is regarded as extending to about 1500 b. c. In his chapter on this period the author describes a considerable variety of tools and