This was one of he most remarkable things I have ever seen in the wild. I was out on the north edge of the Merry Lea Environmental Learning Center of Goshen College, in northeast Indiana, which is bordered by farm fields. Along the wild edge between two fields swirled dozens of monarch butterflies, each of them in pairs, back to back. The male is on the inside, and would hang on to the abdomen of the female as she flew for both of them. Occasionally a pair would stop briefly, and I'd try to get close enough to get a picture--not easy, because they'd fly again if I got too close. I've never seen anything like this since.