說明/ 體長約3.8–4.4 公分，雄蟲複眼紅色，胸腹部亦呈鮮紅色，腹背中央有黑線。雌蟲複眼上褐下灰藍，胸腹部則呈黃褐色，腹背中央黑線較雄蟲明顯。翅透明，翅痣黃褐色，翅基有褐色色斑。生活於平地到中低海拔山區，常見於池塘、沼澤與水田等水域活動，成蟲於4 到12 月出現，雌蟲會以連續點水方式產卵，為常見的種類，數量很多。本校則可於寧靜湖上游與螢火蟲復育區等地觀察到其蹤跡。（陳家駒攝）
It is about 3.8-4.4 cm in length. The male’s compound eyes are red, the thorax and abdomen are bright red. There is a black line at the center of the back of the abdomen. The female’s compound eyes are brown in the upper section and grayish-blue in the lower section. Its thorax and abdomen are yellowish-brown with a more distinct black line at the center of its back. The wings are transparent with yellowish-brown stigmas and brown spots around the base. It lives in plains and low to medium altitude mountains, often seen in ponds, swamps or paddy fields. Adults appear between April and December. The female lays eggs by continuously dipping its abdomen in the water. It is a common species with a large population. On campus, it can be seen in the upstream area of Tranquility Lake and the Firefly Restoration Area. (Photo courtesy of Chen Jia-ju)