Scientific name: Paracercion calamorum dyeri

Habitat: pond, slow-flowing stream

Body length: 26-32 mm

Distribution in Hong Kong: Mainly in north New Territories, e.g. Tan Shan River, Kai Kuk Shue Ha, Wu Kau Tang

Flight period in Hong Kong: February to December

Identification features (male): 

1. Synthorax pruinose blue

2. Dorsum of the 1st to 7th abdominal segment black

3. The 8th to 10th abdominal segment mainly blue

Identification features (female): 

1. Dorsum of synthorax dark brown, lateral pale green

2. Dorsum of abdomen black