Tremendously important entomologist (1825–1883) responsible for classifying approximately half of the insect taxa known in the US; he volunteered for the Union medical corps during the Civil War. Two items: one original 2.25 x 4 carte-de-visite portrait of LeConte in uniform by Gihon and Rixon of Philadelphia, signed on the reverse in black ink, “With the kindest regards of John L. LeConte, Med. Insp’r U. S. A.”; and an ALS, one page, 5 x 8, Philadelphia, August 3, 1865. Letter to Josiah Whitney of the National Academy of Sciences, declining an invitation. In part: “I have to reply that official duty requires me to be present at Washington next week.” In overall fine condition, with slightly trimmed edges to the carte-de-visite and intersecting folds and some surface abrasions to the letter. RR Auction COA.