Scientific name: Gynacantha ryukyuensis

Habitat: pond and stream with canopy cover

Body length: 64-66 mm

Distribution in Hong Kong: Mainly in north and central New Territories, e.g. Sha Lo Tung, Pat Sin Leng, Shum Tseng

Flight period in Hong Kong: May to October

Similar species: Blue-spotted Dusk-hawker, Dingy Dusk-hawker (Comparison)

Identification features: 

1. Mesepisternum without apparent stripes

2. Dorsum of synthorax near the base of forewings with a obtriangular spot

3. Second abdominal segment with a pair of rhombus-shaped blue spot

4. Abdomen slender