Among the loveliest stereoviews I've ever seen for sure, and quite a collectible one I think; I've found several mentions/reproductions of it on sites devoted to stereoviews, and found one other example of it in a notable photography collection. It was photographed and produced by the Kilburn Brothers (Benjamin West Kilburn and his brother Edward Kilburn) of Littleton, New Hampshire, among the most significant of the American photographers and publishers of stereo cards in the 19th century (founded in 1865.) These two hand-colored photographs of mounted moths and butterflies mounted to the perfect yellow card, dates to 1870 or so I believe. Gorgeous.
6 3/4" x 3 1/4" and in good condition, with light general wear and light bump to upper right corner. The print at bottom on the front reads No. 89 Moths & Butterflies, and the card is printed on reverse: Photographed and Produced by Kilburn Brothers, Littleton NH.