Trained as a physician, LeConte made his name in the world thru his collecting and studying of Coleoptera. He has been referred to as the greatest Coleopterist of the country and one of the finest systematists. Not only did he make many collecting expeditions in this country but went to Central America, to Europe, Egypt and Algeria. He was enlisted in the army medical corps during the Civil War and later returned to Philadelphia as Assistant Inspector of the Mint in that city. His extensive collection was presented to Harvard University as the possession of the Museum of Comparative Zoology. This collection included 6,000 types and was to be always available for study and use by his colleague, G. H. Horn of the Academy of Natural Sciences.

The present manuscripts consist of an annotated catalogue of the Coleoptera of the Academy, stressing additions and corrections to his published work. Also included is a paper on lightning bugs which was apparently never published, notations on Hays' Arctic Expedition of 1858, a report as a member of the Committee on Proceedings of the Academy written in 1856 along with W. H. Rand, Joseph Leidy and George A. McCall. Finally several biographical items are included which contain a copy of his will made soon before his death.