Indocnemis ambigua (Asahina, 1997)

Asahina (1997) described the species as Coeliccia ambigua from Tam Dao, Vinh Phuc Province in northern Vietnam, but it has been moved later to the genus Indocnemis.

In his description Asahina pointed out that the venation of ambigua was not consistent with the genus Coeliccia Kirby but with the genus Indocnemis Laidlaw.

In Indocnemis the anal crossing ends on the anal bridge vein (red circle) and not on the wing margin except in one of four specimens examined by Asahina. But, as pointed out by Wilson and Reels (2003) another characteristic of the genus Indocnemis is the presence of four cells between discoidal cell and the nervure descending from the subnode, whereas Coeliccia has just three cells. This species has three cells consistent with the genus Coeliccia. So the term "ambigua" is still appropriate!

Male : the head is mat black, prothorax and synthorax grey (in fact mat black finely pruinosed), the latter with two pale bluish stripes on each side.

The black (not pruinosed) band on the dorsal synthorax contrast with the greyish tint of the rest of the synthorax.

The abdomen is black dorsally, except segments 9-10 bluish tinted.

Caudal appendages also pale bluish ; the superiors much shorter than the inferiors (please note that the photo of appendages was also taken in the field, with the insect alive. With so tiny parts of the body, I can not expect detailed close-ups. Photographing damselflies appendages require other equipment that I don’t have!).

A mating pair

An ovipositing tandem pair

The male remain in tandem with the female while she deposits eggs, termed "contact guarding". Guarding prevents another male from inseminating the female.

This female oviposit into moss at a vertical surface of a rock

I spotted the female very few times. I am not sure that she has been described - not by Asahina at least.

Indocnemis ambigua inhabits montane forest streams. It is known from a limited number of sites in northern Vietnam (Tam Dao only, the type locality) and southern China (Guangxi).

Currently there is only two species recognised in the genus Indocnemis, the other one is I. orang (Förster in Laidlaw, 1907).

Those shots were taken at Tam Dao, along small rocky streams with heavy covert (alt. : 950-1.000 m a.s.l.). Probably the first ones of this species on the internet.

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.