These are two insect and caterpillar engravings by Maria Sibylla Merian, a German-born naturalist and scientific illustrator, and one of the first European naturalists to observe insects directly. In 1679 she published the first of a two-volume series on caterpillars. Each volume contained 50 plates engraved and etched by her. She documented the process of metamorphosis and the plant hosts of many European insects species. She republished her books in Dutch in 1713 and 1714 under the title Der Rupsen, and these two engravings may well have come from those books. They are numbered in Roman numerals in the upper right corner of each engraving, just the way the engravings are numbered in other books by her. Her observations were turned into botanical art, and if you can afford it, a first folio edition about flowers and caterpillars edited by her daughter in 1730 goes for over $40,000. The engraving with plate number XVIII is pretty clean. The overall size is 11 1/8 x 9 1/8 in. wide and the sight size is 6 x 4 5/8 in. wide. The engraving with plate number XXXV has very light foxing on the matte and the image. The overall size is 11 x 9 1/8 in. wide and the sight size is 6 1/4 x 4 7/8 in. wide.