說明/ 體長5.3–8.2 公分，雄蟲胸腹部綠色且具有金屬光澤，翅背翅腹皆深藍色，無翅痣，腹端有肛附器。雌蟲體色綠色或灰褐色，翅背藍色，有白色翅痣，翅腹褐色，本物種以雌蟲特徵來命名。普遍分布於低海拔山區溪流、池塘與湖泊，喜歡停棲葉端或貼近水面做低空飛行，性喜陽光。白痣珈蟌飛行的方式與一般快捷靈活的蜻蜓不同，牠們飛舞時顯得緩慢優雅，身體和翅膀在陽光的照射下透射出深藍色的金屬光澤，很容易吸引眾人的目光。（彭楨儒攝）
It is about 5.3-8.2 cm in length. The male’s thorax is green and has a metallic shine; the upper and undersides of its wings are dark blue without stigmas. At the end of its abdomen is the anal appendage. The female is green or greyish-brown in color; the upper side of its wings is blue with white stigmas and the underside is brown. It is named after the female’s characteristics. It is commonly seen across the streams, ponds, and lakes in low altitude mountains, staying on the tip of leaves or flying close to the surface of water and enjoying sunlight. Unlike other dragonflies, Formosan Jewelwings’ flight is slow and elegant. Its body and wings give off a dark metallic blue sheen in sunlight, easily attracting people’s attention. (Photo courtesy of Peng Zhen-ru)