Suddenly it was not only spring, but summer, and butterflies like this one flapping around on a nearby marsh. The green hairstreak (Callophrys rubi) is a small butterfly flying in spring or early summer. This butterfly normally displays only the underside of the wings and it is green. This makes it difficult to spot if it sits in green vegetation. And thats maybe why I have never seen this butterfly before. But now I have seen it, at least one of them, and even the sun was shining.