The Irish damselfly or crescent bluet (Coenagrion lunulatum) is a damselfly found in northern Europe and Asia to north-eastern China;. It is common and widespread in northern Finland, scarce and local in the Netherlands and Ireland and rare elsewhere. One of its English name comes from the fact that it is found in Ireland but not in Britain. The alternative name, crescent bluet, refers to the shape of the markings on segment two of the male and its scientific name.