MEMOIRS OF THE AMERICAN ASSOCIATION FOR THE ADVANCEMENT OF SCIENCE. I. SALEM, MASS. F. W. PUTNAM, PERMANENT SECRETARY, A.A.A.S. 1875. PRINTED AT THE SALEM PRESS, SALEM, MASS. LETTER OF GIFT. PORTLAND, Aug. 22, 1873. Mrs. Elizabeth Thompson of New York City, to-day elected a member, sympathizing with the purposes of our Association in the advancement of science, and seeing the new crop of young and industrious scientific investigators who are to form the future basis of this Association following in the footsteps of the veterans of science who founded it, and being aware of the financial difficulties which often beset the path of those noble men of science who labor more for truth than for profit’s sake, wishes to place at the disposal of the Permanent Secretary the sum of one thousand dollars, to be used according to the directions of the Standing Committee, for the promotion and publication of such original investigations by members of the Association as may be accepted by the said Standing Committee, to be published by means of this special donation. [Signed] P. H. VAN DER WEYDE. To the Standing Committee of the American Association for the Advancement of Science. REPORT OF THE SPECIAL COMMITTEE ON THE THOMPSON FUND, HARTFORD MEETING, AUGUST, 1874. The Standing Committee of the Association at the Portland Meeting appointed the undersigned a Committee with full power to accept and print such papers as they might deem of sufficient importance to be published by the donation of Mrs. Thompson. In accordance with the duties assigned to them, the Committee have accepted the Memoir by Mr. Scudder on Fossil Butterflies as the first paper to be published by the THOMPSON FUND, and while regretting that the unavoidable delay in engraving the plates prevents their having the gratification of presenting the work at the present Meeting, they believe that the Association and its liberal patron will accept the Memoir as one in every way worthy of the honor thus bestowed. ASA GRAY, } JAMES HALL, } THOMAS HILL, } P. H. VAN DER WEYDE, } _Committee_. J. L. LECONTE, } T. STERRY HUNT, } F. W. PUTNAM, } FOSSIL BUTTERFLIES. BY SAMUEL H. SCUDDER. TO COUNT GASTON DE SAPORTA, OF AIX IN PROVENCE, WHOSE EXTENDED MEMOIRS ON THE FLORA OF THE TERTIARIES OF SOUTHERN FRANCE FORM THE BASIS OF THE BIOLOGICAL CONCLUSIONS OF THIS ESSAY; AND WHOSE UNWONTED COURTESIES HAVE PERMITTED A CAREFUL EXAMINATION OF THE MOST IMPORTANT FOSSIL BUTTERFLIES, THIS MEMOIR IS RESPECTFULLY INSCRIBED BY THE AUTHOR.