120. Hydrobasileus croceus (Brauer, 1867)

Number: 120

Family: Libellulidae

Genus:  Hydrobasileus

Species:  Hydrobasileus croceus

Common name(s): Amber-winged Glider, Zigzag Glider, Water Monarch

Thai name(s): แมลงปอบ้านชายปีกทอง
Habitat: Exposed ponds and lakes (uplands)

Location(s): Khao Yai National Park (22/04/2011) and Nam Nao environs (July-August 2011)

Sightings (by me): Not common but not uncommon, but impossible to see one that has landed.
In flight (that I have seen): July-August (longer, I'm sure)

A large dragonfly I saw battling right in the middle of a natural pond at Khao Yai National Park, was Hydrobasileus croceus. There were two males and a female, which never seemed to land. Instead carried out a number of threat displays, probably because the female was full of eggs (they look bright yellow/green at the end of the female's abdomen (dragonfly closest to the bottom of the picture). Only 1 male seemed to land and that was at an inaccessible tree on the other side of the pond (just my luck!). However, though quite small this image is good enough to identify the species, especially the male top left. They were amazing to watch and were extremely loud when they collided with each other. I hope to spot one in the resting position one day for better quality pictures.

10. Urothemis signata signata (Rambur, 1842)

No: 10 / Family: Libellulidae / Genus: Urothemis

Name: Urothemis s. signata / Scarlet Basker / แมลงปอบ้านกลางปีกแต้มใหญ

Habitat: Open ponds, marshes, uplands & lowlands
Province(s) sighted: Petchabun, Chaiyaphum, Khon Kaen, Chantaburi, Nakhorn Ratchasima 
In flight: April to November / Sightings (by me): Common 

Easily confused with: Crocothemis servilia, Macrodiplax cora, Rhodothemis rufa, Urothemis abbotti, Urothemis signata insignata

Another common dragonfly that loves sunbathing is Urothemis signata signata. It loves perching on sticks and branches in the blazing sunshine. They can be easily confused with Macrodiplax cora (Noppadon Makbun corrected my initial I.D.), but the main difference is that only the latter segments of the abdomen have black dorsal marks, whereas M. cora has black marks all along the abdomen. Also, I think M. cora is only found as north as Bangkok (this bit is not true anymore ... I found M. cora in Khon Kaen.)

The mature male (red form)

Has long legs like Trithemis species.

Here, you can clearly see only the last 2 segments have black dorsal patches, which helps identify the species.

The young male? (yellow form)

I am convinced that there are two forms of this species. Though the red form is far more common, and all start off life yellow (and become red) I have spotted some rather old-looking yellow males and females. Maybe some just don't become red. No idea why.

... a strange male

Here's a male from Chantaburi that has a red face and dark red eyes (the ones in KK have a whitish face) and also it has no distinguishable marks on the abdomen. I saw several like this but were very difficult to get near. 

The adult female (red form)

The female is very similar to the male. They are less easily frightened than the males and seem to like having their photo taken!

Slightly younger female (has a beautiful marbled effect)

Target sighted ... she's about to strike

Young female (yellow form)

Female in the hand ...

Unfortunately, this 'yellow' female I found dead in a spider's web (freshly killed). 

 

... a very old female (that is still yellowish)

I have seen this species in vast, open spaces and farmer's fields to small swampy enclosed areas (but still in the bright sunshine),   and I have spotted them at many locations around the country.  Also, if you spot one, you will probably see lots at the same time.

8. Trithemis pallidinervis (Kirby, 1889)

No: 8 / Family: Libellulidae / Genus: Trithemis

Name: Trithemis pallidinervis / Dancing Dropwing / แมลงปอบ้านไตรมิตรขายาว

Habitat: Open ponds, marshes, lowlands and uplands
Province(s) sighted: Widespread 
In flight: July to December / Sightings (by me): Common 

Easily confused with: None

Trithemis pallidinervis is one of three Thrithemis species known in Thailand and I have now seen all three. T. pallidinervis is a very common winter species that loves sitting on small twigs and grasses in open areas, especially in the hot sun. I have seen many, many specimens right on the edge of water, as well as a good distance away from any known water.

The male

The male varies in colour from yellow (below) to chocolate brown and is easily distinguished by its long legs and wings that point upwards. It also has yellow colouration to the base of the wings.

Hot chocolate...

This is a chocolate coloured specimen.

 Right on the nose...

This photo shows its distinctive purple nose on the same specimen as the one above, which looks really good.

The female

The female is almost identical to the male.

T. pallidinervis is extremely common and I have seen it in many many places, from Khon Kaen to Chantaburi, though I assume it is widespread. It is especially common in the months of October-December, though could be seen at other times. It's a great dragonfly to photograph, not easily scared and is very happy to pose for you!