Emerging Polycanthagyna erythromelas at Ba Vi

Today, March 27, I went to Ba Vi in search for birds, because it was cloudy and cold (14 degrees at Ba Vi). And pretty early in the season anyway. Near the French Camp there is a smallish pond and checking the overhanging vegetation I noticed an Aeshnid hanging from a stick, apparently freshly emerged. The reddish abdomen pointed to Polycanthagyna erythromelas and indeed, that was what it was. The teneral male looks more like the female and not at all like the mature male in coloration. Even the pattern of the adult male on the abdomen is not visible. Also interesting: the postfrons of the mature insect is all black, but here it is clear that the underlying pattern is that of a T-spot. This individual was holding on to its exuviae, which was very clearly that of an Aeshnid. I had already observed a female once on April 4, but this is the first time I have seen it in March.

A cloudy and dark day I had to go to iso 1600, so it is rather grainy.

With flash that problem was solved, but I only had my macro lens with me and internal camera flash, so the result leaves a lot to be desired. Note the black T-spot on the postfrons.

Eventful day at Tay Thien, a few more goodies

This weekend (June 15-16) proved pretty productive at Tay Thien. Apart from the species already described, I encountered about 50 more. Here are a few other highlights

The first was this beautify male Polycanthagyna erythromelas. I saw several females flying about, but this male resting for a short while in a nearby bush was a treat.

And in the lower river stretches were several Lamelligomphus formosanus active. Once you know the species, it is not so confusing anymore.

Another species present in good numbers, towards the evening in the open and during the day in dark clearings, was Macromidia rapida. I was lucky with a male that perched nearby.

The female of Sinorogomphus sachiyoae. Very much like the male in appearance. After these shots she happily continued ovipositing.

Another cool female, Heliogomphus scorpio. The male was active nearby as she was ovipositing near the nunnery. Like the male, very pale (white) metepimeron, unlike Heliogomphus sp., which occurred at the same stretch, but is much yellower.

Here a close-up of her pretty face. Note the horn on the occipital ridge.

There was something else I did not expect, Drepanosticta hongkongensis. I noticed a male at 350m asl beyond the nunnery. Under the microscope it is identical to the specimens from Ba Vi. I thought the species there was known only from that location in Vietnam, but when this is D. hongkongensis, well, in that case it is not surprising it occurs elsewhere. Although the caudal appendages are identical, the anterior lobe of the prothorax is all black, as it should be for D. hongkongensis, unlike the specimens from Ba Vi.

The penile organ, identical

As are the caudal appendages

Polycanthagyna erythromelas

I am reaching the end of species that I have not published on the blog yet, but there are a few more to go. One is Polycanthagyna erythromelas, an aeshnid that is not rare, seemingly, but I have not seen it often. In fact I had only a few females flying by through the months, for instance at Tay Thien, Tam Dao National Park and once a male hanging in a tree over a small pond in a rocky stream on a hill side in Ba Be National Park in early August. I could take a few distant shots before it dropped of its perch and darted off to new and unknown adventures. This is it:

Polycanthagyna erythromelas, male