By subscribing to the entomological periodicals published in this country (a matter of but slight expense) the student may keep abreast of the current literature. Short book reviews or notes published therein call attention to the more important publications in other countries. Moreover, the Zoologischer Anzeiger, edited by Prof. J. Victor Carus, in Leipzig, Germany, and published every fortnight, gives a tolerably complete bibliography of the current entomological literature at intervals of about six or eight weeks. The "Naturae Novitates," published every fortnight by R. Friedlaender & Sohn, Carlstrasse, 11, Berlin, Germany, gives the titles of most recent works and pamphlets. There are also three great annual publications, viz: "Die Fortschritte auf dem Gebiet der Entomologie," published in Wiegmann's "Archiv fuer Naturgeschichte;" "The Zoological Record," published by the Zoological Record Society, in London, England; and the "Zoologische Jahresberichte," published by the Zoological Station at Naples, Italy, which give the full literature of the previous year, discussing the more important papers and giving a list of the new species, besides other information. These three publications are almost indispensable to the student in any branch of zoology, and some one of them at least ought to be found in every public library in the country. The volumes of the "Zoologische Jahresberichte" since 1887 contain no titles upon systematic and classificatory zoology, but only such as refer to biology. A not inconsiderable portion of the North American literature on the classification of insects has been published by the Government of the United States through various channels, foremost among which are the Smithsonian Institution, the U. S. Department of Agriculture, the U. S. National Museum, the U. S. Geological and Geographical Survey, and the various surveys of the Territories. Some of these publications are distributed free of cost; while others, like certain of the publications of the Smithsonian Institution and the Geological Survey, are sold at a moderate price to cover the cost of publication. Many of them are out of print, and can only be obtained through natural history book-dealers.