“From a composite helio-chrome, made by Mr. Ives.” Page 458. Herschel. Plate 11. A. Hoen & Company, Lithocaustic, Baltimore. Collection of and digitalized by the Smithsonian Libraries. In the public domain. via https://archive.org/details/annualreportofbo1901smit/page/n457“Humming birds.” Paine. Page 809. Plate 11. A. Hoen & Company, Lithocaustic, Baltimore. Collection of and digitalized by the Smithsonian Libraries. In the public domain. via https://archive.org/details/annualreportofbo1901smit/page/n808“Butterflies.” Paine. Page 831. Plate X. A. Hoen & Company, Lithocaustic, Baltimore, lithographer. Collection of and digitalized by the Smithsonian Libraries. In the public domain. via https://archive.org/details/annualreportofbo1901smit/page/n830