Side views of: 21. upper organ; 22. left clasp; 23. right clasp. Image from: Scudder, Samuel Hubbard 1888-89. The butterflies of the Eastern United States and Canada with special reference to New England. Cambridge, Author. 1: xxvi + 766 pp., frontisp.; 2: xii +767-1774, frontisp., figs.; 3: viii + 1775-1958, frontisp., pls. 1-89, 3 maps. [published in 12 parts from November 1888 to October 1889]; pl. 36 f. 21-23