說明/ 體長3.5–4.1 公分，雄蟲複眼呈黑褐色，合胸深藍色，上有白點，腹部黑色，第4–7 節處有橙色斑，但某些個體橙斑較少甚至無班點。雌蟲合胸黃褐色，由側面觀之有3 條斜斑，腹部黃色。雌雄翅皆透明，翅痣黑色，後翅基黃褐色。全年可見，分布於平地至低海拔山區，常見於池塘、溪流與沼澤等靜水或流水區域。雌蟲以點水方式產卵，此為蜻蜓常見的行為。本校可於寧靜湖上游與清園觀察到其蹤跡。（陳家駒攝）

It is about 3.5-4.1 cm in length. The male’s compound eyes are black; the synthorax is deep blue with white spots. The abdomen is black, with orange spots on the fourth to seventh segments. Some individuals have fewer orange spots or none. The female’s synthorax is yellowish-brown with three tilted stripes when observed from the side. The abdomen is yellow. The wings of both males and females are transparent with black stigmas. The base of the hindwings is yellowish-brown. It is distributed across plains and low altitude mountains, often seen in still and moving waters such as ponds, streams, and swamps. The female lays eggs by dipping the end of its abdomen in the water, a common practice. On campus, it can be seen in the upstream area of Tranquility Lake and the Ching Memorial Garden. (Photo courtesy of Chen Jia-ju)