Indocnemis orang (Förster in Laidlaw, 1907)

Indocnemis orang is a large size and robust build damselfly, frequently spotted hanging around in dark areas along rocky forest streams, in hilly and mountainous régions.  

The male is just gorgeous : prothorax and synthorax deep black, the latter with violet antehumeral elongated patches. Side of synthorax almost entirely black except for a yellow stripe (covering the interpleural suture if I am not wrong), sometimes very reduced (aged individuals?). Ventral side of synthorax also yellow.

Abdomen entirely black (i.e. both ventrally and dorsally) , except the 2 or 3 last segments which bear dorsal pale blue spots.

Caudal appendages :

 Lateral view

Dorsal view

One day I also bumped into an immature male with yellowish - and not violet - patches on the synthorax dorsum.

Immature male. The violet coloration on the dorsum of the synthorax begin to appear

The female has different colors and markings than the male, especially on synthorax : yellow antehumeral stripes, sides with 2 broad yellow stripes. Abdomen black dorsally, the last segments with bluish dorsal spots.

I spotted also another form quite different. I am sure it is a female of I. orang because a male was guarding her as she was ovipositing. This one has pale blue stripes on sides of synthorax instead of yellow ones. Immature form ?

Many time I saw males defending small territories around temporary puddles on rocks and females ovipositing there (in wet moss, mud, rotten wood or leaves, twigs not submerged). Scene of oviposition in the video below.

Female ovipositing in wet moss, on the edge of a small puddle. The male perched nearby, termed "non-contact guarding". Guarding prevents another male from inseminating the female.

Female ovipositing in a twig fell to the ground, above a puddle.

Indocnemis orang is widely distributed in Asia from northeast India to southern China and Malay Peninsula.

In the hills and mountains around Hanoi, this species is a rather common sight in suitable habitat.