December 8, Xuan Son in the winter sun

This Sunday, I drove to Xuan Son, to see what has changed since I last visited. Like in Huu Lien, water level had dropped, but the good streams were still good. Here too about 30 species for the day, but numbers for most were down. Coeliccia sasamotoi was the exception, being very much in evidence all over the place. What is interesting is that several species recorded for Huu Lien in summer, but completely absent during all our visits this November / December were still commonly flying at Xuan Son. Aristocypha fenestrella and Matrona basilaris were easily found. Also Euphaea masoni, only seen during our first visit to Huu Lien a month ago and not since, was still about in small numbers. What makes them stay on here?

I bumped into the following species: Matrona basilaris, M. taoi, Vestalis gracilis, Neurobasis chinensis, Atrocalopteryx coomani, Vestalaria miao, Noguchiphaea yoshikoae, Heliocypha perforata, Aristocypha fenestrella, R. "arguta" (I took pictures of several in hand, with hardly any orange on S9-10 to quite a bit), Euphaea masoni, Agriocnemis femina, Ceriagrion auranticum, C. fallax, Pseudagrion pruinosum, Coeliccia onoi, C. scutellum, C. sasamotoi, Indocnemis orang, Copera marginipes, C. vittata (I must have overlooked it before), Boyeria karubei, Orthetrum sabina, O. pruinosum, O. glaucum, Diplacodes trivialis, Neurothemis fulvia, Palpopleura sexmaculata, Crocothemis servilia, Trithemis festiva, T. aurora.

Old male Euphaea masoni

Another male with hole in wing

Matrona basilaris, male, was still common

Matrona basilaris, female

Atrocalopteryx coomani, male

Matrona taoi, male, only one and damaged male around

Pretty Coeliccia sasamotoi, male

Ceriagrion fallax, male

One of several captured Rhinocypha cf. arguta, with at least some orange on S9-10.

Very nice male Copera vittata, overlooked previously?

Jewelry

Some 10 Chlorocyphidae have been recorded in Vietnam. To date I have seen 4. A trip to Ba Be National Park in late July produced all these. Aristocypha fenestrella fenestrella is also found along rapid forest streams in Tam Dao and Ba Vi, so closer to Ha Noi. Rhinocypha biforata apparently is a common species, but to date I have only seen it along a small roadside stream on the way to Ba Be. Heliocypha perforata was common on streams near Ba Be, with an apparent preference for somewhat less rapid streams than A. fenestrella, often occurring in close proximity, but A. fenestrella in steeper and more forested sections. Libellago lineata occurred in very different habitat, slow streaming more murky rivers and lakes, like Ba Be lake itself, where males could be observed on floating bits of rotting wood, the same stuff that females oviposit in. To date (14 September) at least A. fenestrella is still common in the right habitat around Ba Vi.

Rhinocypha biforata, male

Libellago lineata, male

Aristocypha fenestrella, immature male

Aristocypha fenestrella, male

Heliocypha perforata, male

Identifying the females is challenging. Content for a later blog entry. And obviously I cannot wait to see  the other members of the Vietnamese Jewels. Seeing these brilliant insects battle it out over the rapids to impress the females, wings flashing, legs outstretched (in for instance A. fenestrella the white front femurs are a striking feature in display) is a treat!