[Out of print.]SPECIAL REPORT, No. 35.--Report on Insects injurious to Sugar Cane. Prepared, under Direction of the Commissioner of Agriculture, by J. Henry Comstock, Entomologist. (1881.) [pp. 11, figs. 3.] [Out of print.]DIVISION OF ENTOMOLOGY.--INSECTS AFFECTING THE ORANGE. --Report on the Insects affecting the Culture of the Orange and other plants of the Citrus Family, with practical Suggestions for their Control or Extermination. By H. G. Hubbard. (1885.) [pp. x+227, figs. 95, plates XIV.] [Out of print.]SPECIAL REPORT.--Catalogue of the Exhibit of Economic Entomology at the World's Industrial and Cotton Centennial Exposition, New Orleans, 1884-'85. (1888.) [pp. 95.] SPECIAL BULLETIN.--The Horn Fly (Haematobia serrata), being an account of its Life-history and the means to be used against it. By C. V. Riley and L. O. Howard. (Reprinted from Insect Life, Vol. II, No. 4, October 1889.) (1889.) [pp. 11, figs. 5.] BIBLIOGRAPHY OF THE MORE IMPORTANT CONTRIBUTIONS TO AMERICAN ENONOMIC ENTOMOLOGY. By Samuel Henshaw. Parts I, II, and III. The more important writings of Benjamin Dann Walsh and Charles Valentine Riley, Washington, 1890. HOW TO OBTAIN ENTOMOLOGICAL BOOKS AND PAMPHLETS. Comparatively few of the works treating of the classification of North American insects have been published as separate books; but such as have been so published, if of comparatively recent date, can be obtained through the regular book trade. By far the greater number of the monographs and synopses mentioned in the preceding pages have been published in scientific periodicals and in the proceedings or transactions of scientific societies. These may be obtained either through the societies or through the publishers; but single volumes of transactions or proceedings, and more especially single papers, are seldom sold, and the older volumes are liable to be out of print. Moreover, the expense attending the purchase of all of the periodicals containing the publications on a given order of insects will be so great as to put them beyond the reach of most entomologists. The custom of placing at the disposal of authors a number of separate copies of their papers overcomes this difficulty to some extent and creates a small supply. Thus it often happens that a person interested can obtain a copy of a scientific paper by addressing the author personally. Many of these separate copies also fall into the possession of dealers in second-hand books, and may be purchased from them. The American Entomological Society of Philadelphia, and also a few other societies here and in Europe, offer for sale from their duplicates many of these authors' extras, and in some cases publish lists. There are, moreover, certain business establishments which make a specialty of the sale of works and pamphlets on natural history, including entomology, and it is chiefly through such establishments that the student is enabled to secure the larger portion of the works needed.