128 BULLETIN 6*7, UNITED STATES NATIONAL MUSEUM. 



& Sons, 269 Pearl street, New York, N. Y. ; Charles C. Riedy, 432 

 Montgomery street, San Francisco, Cal.; Bausch & Lomb Optical 

 Company, 154 Sutter street, San Francisco, Cal.; Thiebaut Brothers 

 (boxes), 2122-23, Lombard street, San Francisco, Cal.; the Simplex 

 Net Company (nets), Ithaca, N. Y. ; Queen & Co. (microscopes, 

 lenses, etc.), 1010 Chestnut street, Philadelphia, Pa. ; Bausch & Lomb 

 Optical Co. (microscopes, lenses, etc.), Rochester, N. Y. ; the Spencer 

 Lens Company (microscopes, lenses, etc.), Buffalo, N. Y. ; the 

 Wiegner Printery (labels), 2234 North Twenty-ninth street, Philadel- 

 phia, Pa.; C. V. Blackburn (labels), 32 Chestnut street, Stoncham, 

 Mass., and the Entomological Society of Ontario, Guelph, Canada. 



OBTAINING AND KEEPING TRACK OF LITERATURE. 



Although some of the books treating of insects can be purchased 

 through the regular book trade, the larger number can only bo secured 

 through dealers in second-hand books. Many of these dealers adver- 

 ties in the various entomological journals. Various societies fre- 

 quently have for sale reprints of articles published in their proceedings. 

 Such are the American Entomological Society, Philadelphia, tho 

 Entomological Society of Washington, the New York Entomological 

 Society, etc. Some of these issue lists of the papers they have on 

 sale. The various foreign dealers in second-hand books issue cata- 

 logues, which are sent free on request. It is cheaper to buy of these 

 dealers directly than through an agency. 



Owing to the great number of journals containing articles on ento- 

 mology, it is often difficult to keep track of the literature on any par- 

 ticular subject. The Entomologische Litteraturblatter, published 

 monthly by R. Friedlander & Sohn, Karlstrasse 11, Berlin, N. T7. G, 

 Germany, at 25 cents a year, contains the titles of the greater 

 number of articles published on insects. The Bulletin de la Societe 

 Entomologique de France and the Zeitschrift fur Wissenschaftliche 

 Insektenbiologie also contain lists of current literature. The Zoolo- 

 gischer Anzeiger publishes a nearly complete list of the literature on 

 all zoology. The Zoological Record, published each year by the 

 Zoological Society of London, contains practically all of the litera- 

 ture. The volumes are usually a year or more behindhand, and are 

 rather expensive. The Concilium Bibliographicum at Zurich, Switz- 

 erland, issues references on cards. A list of works of value in study- 

 ing North American insects is published by the Bureau cf Ento- 

 mology, U. S. Department of Agriculture, and can be obtained on 

 request. 



