188: Coeliccia nigrescens Laidlaw, 1931

Number: 188  / Family: Platycnemidiae / Genus: Coeliccia

Species: Coeliccia nigrescens / Dusky Sylvan* 

 

Habitat: Narrow Forested Streams 

Province(s) sighted: Nakhon Nayok, Kalasin, Sakhon Nakhon 

Sightings (by me): Rare (2-3 males, 1 female) 

In flight (that I have seen): May-June   

Species easily confused with: Coeliccia didyma didyma; Coeliccia didyma didyma

*As there is no common name, I based the first part on the species name 'nigrescens' meaning 'becoming black' or  'darkening' so settled on 'Dusky' and 'Sylvan' which has been used for some species in the genus, so the Dusky Sylvan.

So, one trip in yielded nothing (Pala-U w/f). The next trip to Khao Yai and into Nakhon Nayok, did produce... thanks to November Rain Rain (Facebook name). Thanks to her kindness, I managed to find the rather elusive Coeliccia nigrescens, which I have named the Dusky Sylvan. It is a species that has already been recorded at Nakhon Nayok and, as far as I am aware, one location in the south. However, I found it where I didn't expect it to be... along the edge of the road under the cover of tree cover and darkness. It seemed to be at home in the overflow bit that runs along side the road, but only in one short section. It was reported to be along a path and was commonly seen, both males and females. Unfortunately, I was greeted by torrential rain and seriously poor conditions. The path -- which I found -- was almost devoid of the species... I got a fleeting glimpse of a solitary male that retreated hastily back into the gloom. Fortunately, there were 2-3 males, plus a solitary female under heavy cover. However, with the horrible rain and gloom, photography was really tough. I managed to get some OK shots of the male and a record shot of the female, which will have to do for now. However, I know where it is now and will return in better weather for sure. It is very much like a Coeliccia sp. and has many of the same traits... the annoying speed at which it can retreat when you finally managed to spot one in the gloom and the way they hand from the tips of leaves. It is also incredibly like C. didyma but can be separated by the white appendages and doesn't have a blue patch on segments 9-10. Also, the markings on the thorax are slightly different. 
So, until I return, these photos will have to do. Since then, I have seen it a few times at Phu Phan National Park in both Kalasin and Sakhon Nakhon, where it is more abundant, though does look a little different.

The Male
Very much like C. didyma but can be separated by the end of the abdomen which has small whitish tips. Here is the 'Phu Phan' form...

Here is the 'Khai Yai' form. See how the blue spots of the thorax are heavily reduced.

The Female

I have taken photos of the female at both Phu Phan and Khai Yai and there is rather conflicting views.

This specimen looks very much like C. poungyi and it could possibly be that species. However, I am yet to see a male of that species at Phu Phan NP in around 8-10 trips. Furthermore, take a look at the copula (at the bottom) and the other female (directly below). It is decidedly similar, though C. poungyi seems to have a spot closer to the top of the abdomen, whereas this is a longer spot/stripe that comes from the base. Please correct me if I am wrong. I need to find more specimens.

As you can see, this is 100% C. nigrescens as it had just split after ovipositing. Here, it is more like a full stripe. 

And here is a record shot of the female from Khao Yai, though obviously older. 

The Copula

This copula I managed to photograph at Phu Phan and you can clearly see the similarities with the females at the top.