A Cat Tien goody - Libellago hyalina

To my knowledge there are two species of Libellago recorded from Vietnam. Widespread Libellago lineata I encountered many times and Cat Tien National Park was no exception. It was quite common. But I noticed a male higher up in a bush that seemed to have a different abdominal pattern. Checking it in hand revealed also a different thorax pattern, with a kind of zigzag line. It turned out to be Libellago hyalina, a species known from nearby Binh Duong Province. It was less common than L. lineata, but still I encountered it every day in small numbers. The younger males and the females displayed the zigzag pattern, but later I also saw several mature males, with completely green-metallic thorax, quite different from L. lineata.

Young male Libellago hyalina, showing zigzag pattern on side of thorax and hyaline wingtips.

The female showing the same side pattern, the photo a little hazy due to foggy lenses

A mature male caught along a forested stream, where it was sitting low on weeds. The thorax now completely green and the abdomen showing the extensive reddish brown dorsum. The wing tips hyaline in this specimen too, even if you cannot see that in the photo.

A few cool jewels from Huu Lien

We encountered 4 species of Jewel at Huu Lien, Heliocypha perforata, Rhinocypha biforata, aforementioned Rhinocypha cf. drusilla group and Libellago lineata. These are lovely damsels, brilliantly colored, and especially Libellago, tiny. All were very common in places, apart from the drusilla type, of which we saw only one. Here are a few impressions.

Beautiful Rhinocypha biforata, male

Rhinocypha biforata, female

Stunning Libellago lineata, male

An immature male Libellago lineata

And the female Libellago lineata

Heliocypha perforata, male

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!