Scientific name: Orthetrum triangulare triangulare

Habitat: marsh, pond, slow-flowing stream

Body length: 45-50 mm

Distribution in Hong Kong: Widespread, e.g. Tai Po Kau, Tai Tam

Flight period in Hong Kong: April to November

Similar species: Common Blue Skimmer, Marsh Skimmer, Mangrove Skimmer (Comparison)

Identification features (male):

1. Frons black

2. Synthorax dark brown to black

3. The 8th to 10th abdominal segment all black; Black area on the 7th abdominal segment varies among individuals

4. Black spot on wingbase of hindwing

varies among individuals

Identification features (female):

1. Synthorax and abdomen mainly yellowish brown

2. Two yellow stripes at two sides of synthorax; a disconnected yellow spot may appear at the end of the 1st stripe 

3. Abdomen stouter than Common Blue Skimmer