The founders of the Entomological Society of Philadelphia, the predecessor of the American Entomological Society, stressed the advantages of a library and of a study collection of insects. Donations to the library were recorded for 1860-96 in two ledgers; three catalogs were prepared, 1863, 1864, and 1885; and four accession books show all additions to date. The first three accession books have been checked in red to show the volumes which are on permanent deposit in the Academy's library.