Devadatta ducatrix Lieftinck, 1969

A rocky, well-shaded streamlet, habitat of Devadatta ducatrix

Devadatta ducatrix was described by the Dutch entomologist Maurits Lieftinck (1904-1985) based from one male collected by the German entomologist, insect trader and explorer Hans Frushstorfer. The holotype is deposited in the National Museum of Natural History, Paris, France.

This species loves very dark places but sometimes I have been lucky enough to see it in bright sunshine, which reveal the brilliant blue-grey metallic body of the male. 

I have spotted Devadatta ducatrix in many occasion, in good or degraded forests, in lowlands or mountains, along small running waters on rocky slopes, under tree heavy cover, often in compagny of Coeliccia species, Protosticta satoi, Agriomorpha fusca, Cryptophaea vietnamensis...

It is a rather large-sized, stout bodied species.The male has pro- and synthorax dull metallic blue-grey, both more or less pruinescent laterally; abdomen wholly dark brown with sides of S1-2 slightly pruinescent. All wings dark tipped (in both sexes). 

I often saw the male resting with its wings half spread like a Lestes, showing the dark apices of all wings.

Close-up on wing apices.

I did manage to spot the female, but at few occasions. Unlike the male, she likes to hide away from the water, under the protection of the undergrowth, and only approach the water for mating and oviposition.

She has a brown-reddish body, white stripes on sides of synthorax and white spots along the abdomen. Both male and female show darkened wing apices, but only the female has whitish pterostigma.

A pair in tandem

Prior to copulation, male transfer sperm from the genital pore on abdominal segment 9 
to the accessory genitalia on segment 2

Then, mating begins...

This position during copulation, known as the "wheel formation" because the couple forms a closed circle with their joined bodies, is unique to the order Odonata.

This "wheel", though, looks more like a Valentine heart...

The female was observed ovipositing on fallen vegetation - aerial roots I think.

The male perched nearby guarding his mate while she deposits eggs, termed "non-contact guarding". Guarding prevents another male from inseminating the female.

This species is known predominantly from northern Vietnam, with some records in southern China (Guangxi) and Laos (Vang Vieng).
Around Hanoi, it is not an uncommon sight in the hilly and mountainous localities, along well-shaded rocky streams and brooks, through relatively untouched or degraded forest.

In central Vietnam occurs an another Devadatta species : D. cyanocephala Hämäläinen, Sasamota & Karube 2006, characterized by a conspicuous sky blue face.