Fast-flowing stream with boulders, running through largely untouched forest, Xuân Son
My first 2 days trip of the season: Xuân Son
National Park (140 km north-west from Hanoi). As the weather was cloudy, thus not optimal for forest dragonflies, I chose to focuse mainly on the open aspect streams and
rivers around the park and found there 4 new species for my personal list: Orientogomphus
naninus, Dysphaea basitincta, Pseudagrion spencei and Macromia clio. Other
notable species were Macromia cuprincincta and the recently
described  
Lamelligomphus vietnamensis.
Within the park itself, Phaenandrogomphus tonkinicus was the only new species
for my personal list.
Here are my best photos from this trip:
 
Lamelligomphus vietnamensis, male
 
Recently described from Tam Dao and Xuân Son
NP (Karube, 2015) 
 Lamelligomphus vietnamensis, male
Was patrolling slowly a short section of open river, hovering a lot
Lamelligomphus vietnamensis, male in hand for better view
Lamelligomphus vietnamensis, male caudal appendages, lateral, apical and ventral views
Lamelligomphus vietnamensis, male
Was patrolling slowly a short section of open river, hovering a lot
Lamelligomphus vietnamensis, male in hand for better view
Lamelligomphus vietnamensis, male caudal appendages, lateral, apical and ventral views
  
Note the denticles in the inner corner of the curled part of the superiors, the tip of 
inferior appendage closely apposed to the superiors (no protrusion) - compare for example with the appendages of L. camelus in the photo below
 Lamelligomphus vietnamensis has been recorded
from Tay Thiên-foothills of Tam Dao (Vinh Phuc Prov.) and Xuan Son NP (Phu Tho
Prov.) – type locality. Tom also recorded it from Bac Kan, Thanh Hoa, Lang Son and Cao Bang Provinces.  I
personally found it at Hàm Yên district (Tuyên Quang Prov.) - around the house
of my mother-in-law ! - and at Cuu Thac-Tu Son (Hoa Binh Prov.). So clearly widespread and not rare. 
 
Lamelligomphus camelus, a male assuming the obelisk posture at midday 
The commonest Lamelligomphus in northern
Vietnam. This male has been photographed within the park boundaries. 
 
Lamelligomphus camelus, male caudal appendages 
Note
the distinctive humps on S8, that gives this species its name. Note also the
dorsal tooth at one third of the superiors and the protrusion of the tip of
inferiors.  
Orientogomphus naninus, male, taken from a small river (20
m wide) with moderate flows across agricultural land, with well-vegetated banks
at some sections. 
  
Orientogomphus naninus, male, face 
Orientogomphus naninus, male, caudal append. (dorsal, lateral and ventral views)
 
Habitat of Orientogomphus naninus 
(+ Peudagrion spencei in the grassy beds,
Dysphaea basitincta, Burmagomphus cf. vermicularis on rocks)
Open stream, 15m wide, with gravel/rocks
bottom substrate
The male Orientogomphus naninus was hovering at noon below the
first trees on the left
Habitat of Lamelligomphus vietnamensis,
Macromia clio, M. cupricincta and Dysphaea basitincta 
An open aspect, gravelly bottomed river, with
moderate flows running across hilly landscape covered with tea plantations. L.
vietnamensis were hovering above the small gravelly rapids in the centre of the
image, M. clio were cruising along the beds (quite long distances), M.
cupricincta was caught above the puddle in the left (patrolling back and
forth short distances) and D. basitincta was perched conspicuously on the banks
vegetation.
My 7th Macromia species
 Macromia clio, male
Macromia clio, male
 Blackish face and white postclypeus
Macromia clio, male
Note the yellow labium. Viewed ventrally, it appears broadly edged in yellow
Blackish face and white postclypeus
Macromia clio, male
Note the yellow labium. Viewed ventrally, it appears broadly edged in yellow  
Macromia clio, male, caudal append. (dorsal and lateral views)
 
Found this species in June at Mê Linh-Tam Dao
along a 1,5m wide stream (see my precedent post) 
 Macromia cupricincta - same individual after capture
Note the reddish face, the extreme curve of the wing at the anal triangle, indicative of this species, and the spike on the dorsum of S10
Macromia cupricincta - same individual after capture
Note the reddish face, the extreme curve of the wing at the anal triangle, indicative of this species, and the spike on the dorsum of S10

Macromia cupricincta
Macromia cupricincta, male, tip of abdomen in lateral view
 
Dysphaea basitincta, male – originally
described from “Tonkin” (i.e. northern Vietnam) 
Found at almost all river stretches I checked.
Perched on rocks/fallen branches
in the middle of the river or on the overhanging bank vegetation
Dysphaea basitincta,
wings close-up
The base and apex are black and opaque in both wings, the intermediate are being hyaline 
Pseudagrion spencei, male 
Encountered in the grassy
banks of broad open aspect streams and rivers and in the nearby rice fields
Pseudagrion spencei,
copula 
Smaller than P. microcephalum and P. australasiae,
 different
ocular spots, different caudal appendages, greenish wash along the 
abdomen in the male. The female is also very plain, very different from 
the ones of microcephalum and australasiae 
Pseudagrion spencei, female
 
Mnais mneme, orange-winged male 
Few individuals
encountered. The season is almost over for this spring species. Better no to
use flash with the pruinosed individuals, if not it can really alter their
appearance.
Vestalis gracilis,
male
Better not to use flash for this one also
 
Vestalis gracilis,
female 
Archineura
hetaerinoides, female 
Not the easiest
Calopterygid species to photograph. I'm constantly frustrated by their refusal to
allow close approach. 80-90 % of the individual are very alert, but
sometimes you bump into a tame one which allow a very close approach, as you
can see from my photos.
 Archineura
hetaerinoides, female
Archineura
hetaerinoides, female
 
Phaenandrogomphus
tonkinicus 
An expert hovering Gomphid !
Habitat of
Phaenandrogomphus tonkinicus 
and Chlorogompus
sachiyoae
Ch. sachiyoae was
patrolling back and forth short distance (ca 20m) along the banks
Chlorogompus
sachiyoae, male
Some males were observed (and caught for identification) making slow patrolling flights up and down the stream course, at a height of 0.1m to 0.3m above the stream.
The only Chlorogomphus species recorded at Xuan Son so far.
Seems to be the most successful Chlorogomphus in northern Vietnam – recorded in
many localities, in lowland and mountains. Bust just a few years ago, only known from the
type locality (Tam Dao)! 
 
 Chlorogompus
sachiyoae in hand
Note the particular pattern of S2 
Chlorogompus
sachiyoae, male caudal appendages, lateral and dorso-lateral views
Chlorogompus
sachiyoae in hand
Note the particular pattern of S2 
Chlorogompus
sachiyoae, male caudal appendages, lateral and dorso-lateral views
 
Recently emerged medium-sized Gomphid
I am annoyed that I
can't ID it. Hopefully, somebody somewhere may know (at least determine the genus).
 
 
Perched on leaves, after its first successful flight
 
The exuviae

Libellago lineata 
A pair of males
holding adjacent territories and engaging in agonistic flights
Orthetrum luzonicum,
male