Protosticta grandis is a large-sized robust Platystictid damselfly that I have seen on a few occasions in the good "spots" around Hanoi (Ba Vi, Cuc Phuong, Tam Dao National Parks, Thuong Tien Natural Reserve).
Abdomen pale brown with whitish proximal ring at the end of S3-7. S8-10 entirely dark brownish without any markings.
Caudal appendages of male wholly yellowish.
The female is coloured like the male but has a stouter abdomen.
I have bumped into this species not more than 5 times in 3 years. It's one of those damselflies that is easily overlooked. It can be found in good forests, perching quietly in the dense undergrowth. When disturbed, it flies weakly a few dozen centimetres away. It is inconspicuous in coloration and behaviour for sure, but not more than its much smaller cousin Protosticta satoi - a species I have spotted many times. This tells me that P. grandis is probably a scarce species - not just overlooked.