Maine’s Farnsworth Art Museum is opening an exhibition this month that features about 30 paintings by N.C. Wyeth on loan from the Brandywine River Museum in Pennsylvania. The paintings span four decades of Wyeth’s work and include early western paintings, paintings that were used as illustrations for Robert Louis Stevenson classics, and later illustrations in experimental style. Some of the books in which his illustrations appeared will also be on exhibit. N.C. Wyeth, who died in 1945, split his time between Pennsylvania’s Brandywine Valley and coastal Maine. The Farnsworth museum devotes much of its space to his Maine-related work, as well as that of his son Andrew and grandson Jamie. The new exhibition opens April 27 and runs through Dec. 29.