Macromidia kelloggi - a relatively solid Macromidia

In 2015 Karube published a record of Macromidia kelloggi from Bach Ma National Park close to Da Nang. This was far from known localities in China, but Karube postulated that the species in fact occurred widely in northern Vietnam. Because it has yellow antehumeral spots it is quite easy to separate from the common Macromidia rapida, but although I checked many, I never saw this species mixed in.

But today I was staking out Chlorogomphids (in vain) at Tam Dao when around quarter to four in the afternoon, so bright day, although it was cloudy with only intermittent sunshine, when a sturdy Macromidia tried to zip past me. But alas, it ended up in my net. Not only was it immediately obvious that this was not M. rapida because of its sturdiness and different appendages, it also had yellow antehumeral spots! Macromidia kelloggi, I presume? Indeed, indeed! A largish species, total length 60mm and hind wing 39mm.

Macromidia kelloggi. Note the yellow antehumeral spot (although small for the species)

Black base to ivory superiors and brown edged and tipped epiproct

Rather unlike the appendages of M. rapida (see under that species)

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

What goes there in the shade - Idionyx and Macromidia

May 17 and 18 at Tam Dao I was lucky enough to run into several of those interesting Cordulids that lurk mostly in shady places, dart out over shaded clearings in erratic flight and otherwise hang somewhere in the dark. Only under cloudy conditions or towards the end of the day do they really venture out in the open, but they are sometimes quite common. These are the Idionyx species, with their imposing appendages, and the Macromidia species. They look superficially quite similar, although the males of Macromidia miss the weird appendages of Idionyx. The females look even more similar. I saw a few Idionyx carinata females on the Tam Dao 2 trail, so at around 1000 m asl. But in the lowland stretches of the streams in the Tay Thien area I saw several handful. The problem of course that they are difficult to catch and I only managed females. Checking in the field they had no horns, so I thought they would all be Macromidia. One was decidedly larger but the four others were all the same small type with large yellow basal markings to the wings. Under the microscope there are interesting differences in the shape of the vulvar lamina. The one female had the lamina shaped into a deep V as is normal in many species. But the smaller specimens had the two halves firmly closed together. This did not look like the same genus after all. The larger species is Macromidia rapida, a common species in the Tam Dao area, although not easy to find. Although M. genialis shanensis could also be present, that species has some different markings on the thorax and face. It also, apparently, misses the small brown markings at the base of the wing. The smaller species in fact belong to a group of small Idionyx that miss horns on the vertex. This could be either I. yolande, I. victor or I. thailandica. I. yolande and I. victor have a slightly different thorax pattern (although that of the female published by Karube (2011) looks very similar). I. victor also has apparently less yellow at the base of the wing. The present species is therefore I. thailandica. In fact Sebastien Delonglee also reported having caught this species in the Tay Thien area (including males). I too will be keeping my eyes open for the male in the next few weeks. Coincidentally, what also separates these small Idionyx species from Macromidia are the yellow shins and the different ventral pattern.

Macromidia rapida, female, and Idionyx thailandica, female

Macromidia rapida, female. Note brown on dorsum of thorax, brownish-yellow face and dark brown bases to the wings.

Idionyx thailandica, female. Note yellow shins (not just this species), large ochre bases to the wings and lack of obvious lamina in lateral view (again, indicative of the genus, not the species). The straight yellow line over the spiracle is indicative of the species.

Idionyx type of vulvar lamina

Macromidia type of vulvar lamina

In lateral view, no obvious lamina visible for Idionyx

But obvious for Macromidia

Belly pattern of Macromidia rapida, female

Very different belly pattern of Idionyx thailandica/yolande group of females

Macromidia rapida

In Cuong's checklist on the dragonflies of Vietnam one Macromidia species is mentioned, M. rapida. It is not the only species occurring in Vietnam, as proven by Sebastien Delonglee, who also recorded M. genialis shanensis (see his blog for more information). It maybe is not uncommon, just hard to find. I saw it in the foothills at Tam Dao National Park, where three males were battling it out for some reason known to them in a dark corner of a rocky stream, near a tiny sandy beach, mid August. The next day I also saw two females ovipositing in small feeder streams of the rocky stream. I am sorry that the photos did not turn out like I hoped, but for the time being, this is what we have to make do with. The appendages of the male or whitish apart from the tips and bases, different from M. genialis, which has them all black.

Macromidia rapida, male

Macromidia rapida, female

Tip of abdomen of female

Dorsal view of appendages of male