Labrogomphus torvus Needham,1931

Female Labrogomphus torvus at Huu Liên Nature Reserve, on December 1, 2014,  
enjoying the first rays of sunshine on a fresh winter morning

Labrogomphus is a monotypic genus erected by Needham (1931) to receive a female specimen of Labrogomphus torvus collected from Hainan. Chao (1954) described the male and larvae specimens collected from Fujian. It is allied to Macrogomphus, with which it agrees in having the 9th abdominal segment more than twice as long as the 8th.  
Labrogomphus torvus is a stunning blackish spiny-legged species, with a thorax handsomely striped, a curved abdomen spotted with bright yellow.  
I was lucky enough to spot both male and female the same day, in December 2013, at Huu Liên, as I wandered along a reservoir's banks.

One of the most impressive Gomphid species I have been privileged to see in Vietnam so far - the very long hind legs armed with extremely long strong spines have probably something to do with this.

... before grabbing few meters away her breakfast, a female Orthetrum pruinosum 

A voracious predator !

This stupid male landed on my net! (I read somewhere that white nets attracts certain groups, namely gomphids. Seems true...) 
Note S9 markedly elongate, S7-9 broadened and the large basal ring on S7.

                             

Male in hand. Hind femur and tibia with very long spines

Female in hand - same stuff on hind legs

Male, head. Note the particular shape of occipital ridge.

Compare with the female :

Male, caudal appendages, lateral, dorsal and ventral views

Labrogomphus torvus is known from southern China including Fujian, Guangdong, Guangxi, Anhui, Hainan Island, Hong Kong. In December 2013, it has been discovered at Huu Liên, first record for Vietnam. In June 2014, I also found it at Tây Thiên (foothills of Tam Dao) along a rather open rocky stream in degraded secondary forest and Tom Kompier recorded it the same month at Ba Be (Bac Kan Province).

According to literature, this Gomphid can inhabit a wide range of stream and river habitats, both in forested and open aspect environments, and even ponds/lakes created by impounding streams - it was the case at Huu Liên.