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)

Hemicordulia tenera - an emerald at Da Lat

April 17 I caught a medium-sized emerald along the edge of Tuyen Lam Lake, at one of the swampy corners of the lake where a small stream runs into it and creates boggy conditions. It was ovipositing in a pool surrounded by grasses. It is always a happy occasion to bump into emeralds, no matter where you are in the world. They tend to be scarce. In Vietnam I have only seen Procordulia asahinai, but that was at Sa Pa. Da Lat is a different world, of course. It is of course possible that there are undescribed emeralds in Vietnam and I did my best the day after to find the male, but I could not. As far as patterning and the vulvar laminae are concerned there is no reason why this would not be the female of Hemicordulia tenera, a species that occurs for instance in nearby Thailand. Here are a few pictures.

Female Hemicordulia tenera. She has long legs, that is for sure.

Scan of the same female, showing the venation.

Somatochlora dido - another Sa Pa goodie

This weekend we went to Sa Pa to search specifically for a quite brilliant and seldom seen emerald, Somatochlora dido. This is an autumn species, seemingly flying from August to October. Sebastien Delonglee has some stunning photos of the species on his blog and clearly I wanted to see this species for myself. So we drove to the Love Waterfall area and arrived at 10.30 in the morning to see several males almost immediately. Just as well, for clouds started to build up before I got a few shots in and after that we had to wait quite a long time for a few short spells of sunshine, during which one male reappeared. I was able to make some quick in-flight shots before it took off again and it became cloudy once more. Hopefully I will have another and better opportunity later this autumn, but for now I am just happy that we saw it.

The species was described by Needham in 1930 from Sichuan. It has been recorded from a few scattered high-mountain locations in southern China. Wilson synonymised S. dido with S. taiwana from Taiwan, after finding that specimens from Guangxi were intermediate in the structure of the appendages. It is interesting to note that specimens from Taiwan seem to miss to first lateral stripe, which is so prominent in S. dido. Be that as it may, S. dido was recorded in 1995 by Asahina from the same general location as where Sebastien found it again in 2012 and 2013. To this we can now add my own 2015 records. So far the only site known from Vietnam, although it may be occurring in the forest around Fansipan. There are various bogs in there, although difficult to access because entry is restricted.

Somatochlora dido, male. Note the diffuse orange-yellow postclypeus and bright yellow labium, and the two yellow lateral stripes.

This species hovers about 1-1.50 m high over trickles in acidic swamp areas and flies amongst tree tops when hunting

Procordulia asahinai - Cordulids rule!

May 17 I was checking a small pond in the Sa Pa area when I noticed a medium-sized dragonfly hovering over the water. Before I could find out what it was, it had disappeared, leaving me puzzled. But the next day when I returned around noon it was there again and it turned out it was a smallish Cordulid, something I did not expect at all. I thought it might be a Hemicordulia species, but checking the literature I came across a species that looked quite similar and had been described from Tam Dao by Haruki Karube in 1997: Procordulia asahinai. At the time he also first thought he had collected a Hemicordulia species, but small auricles and a cross-vein in the anal triangle showed it was a Procordulia. I immediately checked my specimen for these characteristics and…BINGO! After that it was easy. This was Procordulia asahinai, a species occurring in the higher mountains of northern Vietnam. I love Cordulids, so a happy day!

Male Procordulia asahinai, a pretty species

The face in frontal view

Hamule in lateral view

Appendages in dorsal view

And the same in dorsolateral view

Another name change: Idionyx claudia, I guess she had to go

Keith Wilson already pointed out to me that Idionyx claudia does not have short antehumeral stripes and that he therefore could not believe that the species I found in Xuan Son late May was in fact this species. I failed to update the blog, also because I left some uncertainty in my entry as to the specific identity. But I have had already for a while a suspicion that it is a species described by Asahina in his work on Thai Odonata, Idionyx selysi. The citron yellow anteclypeus and labrum combined with the short yellow antehumerals, the brownish suffusion to the wings in addition to the amber basis, the simple vulvar lamina and the dent in the posterior edge of the second dark lateral stripe towards its dorsal end all point to this species, although the legs are possibly oddly dark and the anal loop has too many cells (but this is also the case for all female I. thailandica that I scanned in comparison with Asahina's description. So, I changed the entry and will look for the male when spring comes.

Idionyx thailandica

June 14 I caught a male Idionyx thailandica near Tay Thien. I had also caught several in Huu Lien on May 25, but to my dismay I forgot to publish them. Hamalainen described I. thailandica in 1985. In 1991 he also described I. victor from Hongkong. I am a little confused by these species. The descriptions do not really give an answer as to why these are different species. Hamalainen states that the lateral expansion of S7-9 is distinctly  wider in I. thailandica than in I. victor. The appendages are (almost?) identical. Based on the lateral expansion criterium my specimens are all I. thailandica.

Idionyx thailandica, male, Huu Lien, May 25

The same male, different angle

A different male on the same day, same location

Young male I. thailandica, Tay Thien (Tam Dao), June 14

Face of young Tay Thien male

Appendages in dorsal view of Tay Thien male

Same in lateral view

And in ventral view

Huu Lien male appendages in lateral view

Idionyx selysi - or….*

* This entry was adjusted on December 23. The species name was changed from I. claudia to I. selysi.

May 31 and June 1 I was in Xuan Son National Park and encountered many smallish Idionyx females, all females, scurrying around in semi-secluded areas in the forest or at darker moments in slightly more open places. They all had in common that they had a very bright light-yellow labrum and smoky wings. The also had short antehumeral stripes. With I. thailandica / victor they shared lateral thorax pattern and a rounded vertex. But that facial pattern, those dorsal thorax markings and smoky wings… Actually I am still a bit at a loss here. But checking Asahina I found that his description of Idionyx selysi fits the present species well. The combination of bright-yellow labrum and anteclypeus, the lateral thorax pattern with a characteristic bite out of the posterior margin of the second dark lateral stripe, the brownish wings, the rounded frons, the small vulvar lamina forming a simple crest, this all fits well. The legs seem oddly dark though, and the anal loop has too many cells. But for the moment and until I catch a male, I think this is the safest bet. I am not aware of any Idionyx species in the region that has such brownish wings. But maybe someone has another suggestion. In the meantime, let's find the male!

Idionyx selysi occurs widely in Lao PDR, in Thailand and Myanmar. It is suggested that its occurrence in Vietnam should not come as a surprise.

By the looks of it: Idionyx selysi

For comparison. I thailandica. Note slightly different thorax pattern, S1-2, yellower tibia and of course wing color

Face of I. selysi (?) with very light-yellow labrum and anteclypeus.

Thorax pattern, showing the short antehumeral and the dent in the posterior edge of the dark stripe over the metapleural suture towards its dorsal end.

Scan in dorsal view, note many more cells in anal loop

I. thailandica for comparison

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

Tying up some loose ends from Yen Bai

There are some loose ends, various interesting (I hope) photos from Yen Bai from the weekend of May 10 and 11 that I would like to share.

For one, I saw a great many Mnais andersoni this time. What is very interesting are two aspects. None of the orange-winged males (many) had a pruinose dorsum to the thorax, quite contrary to what I noticed for M. mneme. On the web there are many photos with pruinosity, but I fail to find ones that also show the penile organ to show the true identity of the species. For the populations here it seems a consistent difference. The other aspect of interest was that the hyaline-winged specimens were far outnumbering the already quite common orange-winged ones. This also is very different from the population of M. mneme in Xuan Son, where the hyaline males are rare.

A mature male hyaline-winged form of Mnais andersoni

And the same for the orange-winged form. Note the complete lack of pruinosity on the dorsum of the thorax.

Another interesting aspect these two days was the common appearance of Idionyx carinata. I doubted for a moment that it was this species and not something similar, but the males that I caught were clearly I. carinata. Females were variable, some showing only a small yellow spot on the anteclypeus, but other showing all yellow labrum.

Female Idionyx carinata hanging from a twig

Face of one female Idionyx carinata with only limited yellow and single horn

Another female Idionyx carinata with almost completely yellow labrum and double horn

One of several males caught, clearly I. carinata

As his "thing" shows

Another interesting observation was of a female Devadatta ducatrix. Below a photo:

Female Devadatta ducatrix, more colorful than the male

The male of Idionyx carinata

One of the reasons why I went back to Huu Lien, apart from the Gomphids, was to look for the male of Idionyx carinata. I saw several females cruising in the forest and eventually there he was, the male. Always good to find that your earlier identification was correct. The male has a small yellow spot on the anteclypeus like the female and the thorax pattern is the same. The proof of the pudding is in the massive and strange appendages. What do they do with this?

Idionyx carinata, male, such a friendly little chap

That is, until he shows you his "thing" 

Idionyx carinata at Huu Lien

April 21 I was checking for dragonflies inside the forest in Huu Lien Nature Reserve in the afternoon under a cloudy sky. My attention was drawn by a dragonfly cruising up and down a slight opening over the trail. Caught, it appeared to be a female Cordulid. Checking at home it became quickly apparent this is an Idionyx species. Karube (2011) described 3 species for Vietnam, Idionyx victor, I. carinata and I. asahinai. The latter two have the same thoracic markings are my female and the double horn on the vertex points to I. carinata. A further difference with I. asahinai is the facial pattern, with a small yellow spot on the center of the anteclypeus, whereas in I. asahinai the whole labrum is also yellow.  

I. carinata is widely distributed in Southern China and apparently also in Northern Vietnam, as Karube mentions specimens from Tam Dao, from Cuc Phuong and also from Cao Bang Province. By the way province is the province west of Lang Son, in which Huu Lien is located. 

Fraser (1924) mentions I. optata as very similar to I. carinata, but states for instance that the anal loop of carinata has less cells (4-6 cells in carinata and 12 in optata). However, this was based on only one female and one male specimen. The photo of I. carinata in Karube show around 12 cells in the loop. My specimen also has 12 cells. Of course I will be happy to see a male next time!

Idionyx carinata, female, scan of dorsal side

Same female in ventral view. Note the straight yellow stripe and the extensively yellow metepimeron, yellow extending onto metepisternum.

Note the double horn on the vertex and the small yellow spot on the anteclypeus (and extending marginally onto the labrum)

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