Wednesday, October 15, 2014

03. Agriocnemis pygmaea (Rambur, 1842)

Agriocnemis pygmaea (Rambur, 1868)
Number: 03
Family: Coenagrionidae
Genus:  Agriocnemis 
Species:  Agriocnemis pygmaea (Rambur, 1842)
Common name(s): Pygmy dartlet, Pygmy wisp
Habitat: Ponds, lakes, rivers associated grassland   
Distribution: Dhaka, Sylhet, Chittagong 
Abundance: Common 
Flight season: All seasons of the year
Similar species: Agriocnemis femina, Agriocnemis pygmaea 

Agriocnemis pygmaea, a closely similar species of Agriocnemis femina, is a small damselflies often found in the grassland associated to water bodies. They are tiny, maintain small territory, stay close to ground and flight slowly within a short range. Due to their small size often they become prey of many other damselfles and dragonflies. 


Agriocnemis pygmaea is morphologically similar to Agriocnemis femina. The length of the abdomen is 16-17 mm and the length of the hind wing is 9-10 mm. The eyes are green, black capped, post ocular spot present. Thorax is black dorsally marked with apple green antehumeral stripes and green laterally. Legs are whitish. Wings are transparent, Pterostigma pale yellow in the fore wing, black in the hind wing, 6-7 post nodal vein in the fore wing 5-6 in the hind wing.   

Black stripe travels from segment 1 to segment 7 dorsally, pale yellow laterally, segment 1 and ventrally green. Segment 8-10 and caudal appendages orange.  

Like many other female damselflies Agriocnemis pygmaea shows different color morphs, mainly red morph and green morph. Eyes are pale green, brownish cap above. Broad black stripe in the thorax, associated with adjacent thin bluish stripe. Legs are whitish with black spines. 

Wings are transparent with golden pterostigma.  Abdominal segments are red, with apical black ring in segment 2-6. Abdominal segments 7-10 are dorsally black, Caudal appendages are red.

In green form blue post ocular spot are visible. The antehumeral stripes are blue, thorax is laterally green. The abdominal segments are dorsally black and laterally green. 

Both the red and green morph are seen in matting. They usually perched from the grass while matting. Matting lasts for a few minutes.

Distinguishing A. femina from A. pygmaea is very difficult, however by close comparison of the anal appendages it can be done. 



No comments:

Post a Comment