Common Blue Skimmer

Scientific name: Orthetrum glaucum

Habitat: stream, marsh, pond, nullah

Body length: 42-51 mm

Distribution in Hong Kong: widespread, e.g.Tai Po Kau, Mui Wo, Cheung Chau

Flight period in Hong Kong: January to November

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

Identification features (male): 

1. Frons dark brown

2. Eyes dark blue

3. Synthorax dark blue in recently mature individual; Synthorax pruinose pale blue in aged individual

4. Amber spot on wingbase of hindwings

5. Abdomen mainly blue, black at the end

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 thinner than Lesser Blue Skimmer’s