Archibasis viola, another Archibasis in Cat Tien

November 16 Kameliya and I went to the Birdlake area in Cat Tien. Close to where the trail starts off the main track there are a few clean ponds with a lot of floating and emergent vegetation. This is where I noticed a purple damselfly. Identification was straightforward. Archibasis viola, a species that has, according to the IUCN website, been reported from Vietnam, although this is based on non-published information. A. viola occurs all over South-East Asia in wet low-land forest and swamps, so it is not surprising it also occurs in Cat Tien. Interestingly we also bumped into the only male and female of Archibasis oscillans of the trip not very far from this spot, bit at a small stream inside the forest. Both the male and the female were sitting there on a bush. Of A. viola I saw several tandems, but could not get photos of the female. For A. oscillans I could, a nice addition to the material from August.

The male of A. oscillans. The flash makes it appear less bright blue than it is in reality.

Archibasis oscillans, female, after release (hence the smudges on the wings). Note the bite out of the antehumeral, just like in the male.

Male A. viola, less purple under the flash, but still obviously purple.

Close-up of a different male. Note purple labrum and anteclypeus, lack of purple lines on occipital ridge, straight antehumerals. On S2 the typical Archibasis square spot.

Lateral view doing more justice to its purple colour.

A. viola appendages in ventro-lateral view

Same in dorsal view

Same in lateral view