Appearance
Black Stream Glider or Trithemis festiva is a medium sized dragonfly with purple color on its body structure.In the Male, the frontal area appears darker purple-ish grey. The eyes are dark brown above, with a purple colored tinge, which is blue-ish grey, lateral and beneath. The Thorax is Black, covered with purple pruinescence, which helps it appear deep blue. The Legs are black and wings are transparent with a dark opaque brown mark at the base of hind wing, with a black spot on tip of the wing. The abodomen is covered with fine blue pruinescence.
The Female looks dirty brown in the front and extends above. The eyes are dark brown above and appear more grey-ish below. Thorax is Greenish Yellow to Olivaceous, with the presence of a medial dark brown lateral stripe. In addition, a Y-shaped inverted stripes can be observed on the sides. Legs are Black with anterior femora being yellow on the inner side. Wings are transparent with dark reddish-brown tip with a black spot, similar to the Male. Abdomen appears bright yellow with medial, lateral and ventral stripes, colored black, however, the medial and lateral black stripes form a confluence at abdominal segments to enclose a wedge-shaped yellow spot.
Size: Male: Abdomen: 22-28mm, Hind wing: 26-32mm.
Female: Abdomen: 21-24mm, Hind wing: 29mm.
Behavior
They have been observed to be little shy to human beings approaching them, however they are good observers of human beings. Even though people don't notice them, but these dragonflies watch the activities of human beings near them. Its flight activity is at the peak between May and November, but can be seen in other seasons only in quite small numbers, throughout oriental regions.References:
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