Fiery Emperor

A. immaculifrons has a length of 80–86 mm (3.1–3.4 in) and a wingspan of about 120 mm (4.7 in). It is a large, bluish green dragonfly with sapphire-blue eyes, bluish-green thorax, and pale reddish-brown abdomen marked with black. Its thorax is pale bluish-green on dorsum with a blackish-brown mid-dorsal carina and turquoise-blue laterally. There is a narrow black stripe over humeral suture and a very broad one over the postero-lateral suture with a narrow black posterior border on metepimeron. Wings are transparent with amber-yellow tint. Segment 1 of the abdomen is entirely black. Segment 2 is turquoise-blue, with a mid-dorsal transverse mark shaped like a sea-gull in flight. Segment 3 has its basal half turquoise-blue and apical half black, with a small mid-dorsal spot on blue. Segments 4 to 8 are with apical half black and pale reddish-brown at base. Segments 9 and 10 are black on dorsum. A more reddish form from southeast Asia and southern China was formerly included in this species, but in 2022 was recognised as a separate species, A. aurantiacus.

A. immaculifrons is found near slow flowing hill or mountain streams where it breeds. Eggs are inserted into reeds emerging from water.