About Calopteryx xanthostoma (Charpentier, 1825)
The western demoiselle, also called the yellow-tailed demoiselle (Calopteryx xanthostoma), is a damselfly species in the family Calopterygidae. This species replaces the banded demoiselle (C. splendens) in southern France and the Iberian Peninsula. It is sometimes treated as a subspecies of the banded demoiselle, and hybrids regularly occur in overlapping range areas. Male Calopteryx xanthostoma usually have more extensive wing colouring than male banded demoiselles, and their colouring typically extends all the way to the wingtips. Unlike male C. splendens, newly emerged adult male C. xanthostoma have clear wings, and only develop their characteristic wing colour during their first week as adults. The colour of the underside of the abdomen tip is sometimes cited as an identification feature: this area is described as yellowish in C. xanthostoma and whitish in C. splendens, but some sources note this trait is unreliable. Females of this species are metallic green with clear wings, and are nearly identical to female C. splendens. They are difficult to tell apart even when examined closely in hand. This species inhabits areas around running watercourses including streams and rivers, most commonly in open or moderately shaded locations.
