Friday, July 3, 2015

38. Trithemis festiva (Rambur, 1842)

Trithemis festiva (Rambur, 1842)  

Trithemis festiva (Rambur, 1842) 

 

Number: 38
Family: Libellulidae
Genus: Trithemis  
Species: Trithemis festiva (Rambur, 1842) 
Common name: Black Marsh glider
Habitat: Streams, waterfalls
Distribution: Chittagong, Sylhet 
Abundance: Common 
Flight season: March - August

Trithemis festiva one of the four trithemis species found in Bangladesh. The species I have sighted from Chittagong and Sylhet. Commonly, the species is observed nearby streams, waterfalls and stream associated forest patches. The species is distinguished from other species by its black color, bluish abdomen and yellow markings in the abdominal segments. 

                                                             Male

The male has blue thorax, legs are black, wings are transperant, yellow patches present in the wing base. 


I have observed the male from Khagrachari near richag water falls. The male was perching in the reeds of the streams.  


As the male gets older, it become more black. The thorax turns black from blue. Also, the abdominal yellow markings abolished. 





Thursday, July 2, 2015

37. Trithemis aurora (Burmeister,1839)

Trithemis aurora (Burmeister,1839) 

Trithemis aurora (Burmeister,1839) 

 

Number: 37
Family: Libellulidae
Genus: Trithemis  
Species: Trithemis aurora (Burmeister, 1839) 
Common name: Crimson Marsh glider
Habitat: Streams, waterfalls
Distribution: Chittagong 
Abundance: Common 
Flight season: March - August

Trithemis aurora is very common, in fact, it is the most abundant dragonflies in the hilly regions of Chittagong. I have sighted hundreds of them in khagrachari, near waterfalls.  

                                                                 Male

The juvenile male are orange in color, the hind wing base has dark orange patch. The veins are orange, wing transperant, pterostigma black. 

the adult are spectacular colorful insect with scintillating reddish-pink color. The thorax and head is magenta in color, wing transparent, veins reddish. Lega black, anal appendages anterior red, posterior black.   


Female

The famales are less abundant than male and stay away from waterbodies except their breeding period, The females are like juvenile male, can be distinguished by looking att their anal appendages.