Family: Libellulidae
Genus: Brachydiplax
Brachydiplax chalybea

Blue Dasher

Found in Asia: China, Indonesia, India, Cambodia, Myanmar, Malaysia, Philippines, Peninsular Malaysia, Thailand, Viet Nam

Identification Guide to Brachydiplax chalybea.
A widespread species in Borneo Island



The 6th image is difficult to decide between Brachydiplax chalybea and Raphismia bispina

Brachydiplax chalybea is common in Tawau. But Raphismia bispina I have never seen on in Tawau yet.



body length = 36mm
hind wing = 26mm


bl = 30mm
hw = 24mm


1 Though a widespread species, the female of Brachydiplax chalybea is seldom seen. The brownish female only appears to mate and oviposite in the afternoon after which back to the hiding bush again.
2 The brownish female is completely different in color to the powder blue of the male. I would not be sure this is a Brachydiplax chalybea if not I spotted them in a pair earlier ( The blue male being immediately recognize). The mating time is only few seconds after which the female oviposit alone.
3 A sticky egg mass in segment 9 surrounded by jelly . Brachydiplax chalybea’s egg is pale blue in color. Eggs of most other dragonfly species are yellowish.

Female dragonflies produce a sticky substance surrounds the eggs. The sticky substance keeps the eggs together and holds the eggs to an anchor to the plants in the water.
4 Wing venation of a female. Both wings are clear with tinted brown at the base.



雄蟲複眼上半褐色、下半綠色•頭及額是有金屬光澤的藍色.  體長34-38mm


腹部1-5節灰色,前3節具黃斑,後五節黑色, 腹末段黑色,翅膀透明,翅基褐色, 翅痣黃褐色





Brachydiplax chalybea is a moderate sized dragonfly commonly found in unshaded body of water, such as ponds, stagnant or slow flowing streams and drains. The males are a powder-blue in colour with hindwings that are tinted brown at the base and are often seen perched by the water and every now and then flying out to challenge any intruder that wanders into their small territory.



Brachydiplax chalybea is powder blue of moderate size. The hindwing is clearly tinted brownish-yellow at the base. It is a common dragonfly most frequently encountered species of Anisoptera in lowland Borneo, found on virtually any open body of standing or slowly flowing water including artificial drains and dams. It is commonly encountered at the landward margins of mangroves. Typically males establish small territories of a few square metres, and contests are frequent and protracted especially in the latter part of the morning. Mating and oviposition occur in the afternoon.

Males  pale to mid powder blue. Females have shades of brown.

Like most Libellulids they tend to perch on sticks, reeds or stones near water, flying out to catch insects then returning to their perch



  1. Brachydiplax chalybea chalybea Brauer, 1868

  2. Brachydiplax chalybea flavovittata Ris,1911

  3. Brachydiplax farinosa Krüger, 1902

  4. Brachydiplax sobrina (Rambur, 1842)



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