Friday, February 20, 2015

Yellow birdwing (Troides Helena)

Common Birdwing 

Scientific classification
Species:T. helena
Binomial name
Troides helena

Upperside of forewings are rich velvety black with adnervular pale streaks on either side of the veins beyond the cell. The cilia is short, black, alternated with pale buffy white in the middle of the interspaces.

Hindwing: the abdominal fold, the apical half obliquely of interspace 1, the termen broadly, the base of the cell and the costal area up to and including the basal half of interspace 7 velvety black, the rest of the wing rich silky yellow; the veins prominently but narrowly black; the inner margin of the terminal black border produced inwards into prominent cone-shaped markings in the interspaces.

All specimens have one or more postdiscal black spots in the interspaces, but never a complete series; in interspace 2 and sometimes also in interspace 3 these spots coalesce with the cone-shaped projections of the terminal black border. Underneath the abdominal fold is a dense mass of buffy-white scented cottony pubescence. Underside similar, the adnervular pale streaks on the fore wing broader and more prominent.

Hindwing: dorsal margin broadly black, with an edging of long soft black hairs; interspace 1 with a large oval postdiscal and a terminal black spot; interspace 2 with the postdiscal black spot generally separate from the cone-shaped projection of the black terminal border; the apical and lateral margins of interspaces 2-6 pale yellow irrorated with black scales.

Antenna, head and thorax black, the collar narrowly crimson; abdomen yellow, shaded above with black; beneath: the thorax with a large lateral patch of crimson, the anal segment prominently buff-coloured.

Upper and under sides of the female is similar to those in the male, but with the following differences:

Forewing: the adnervular pale streaks broader and more prominent.
Hindwing: the black at base and along the costal margin broader, occupying fully one-third of the cell, the area above it and above vein 7, interrupted however, in interspace 7 near the apex of wing, by a transverse yellow mark which is sometimes subobsolete ; a postdiscal series of large oval black spots, those in interspaces 2 and 3 often joined on the upperside to the cone-shaped terminal black marks; dorsal margin also more broadly black, without the fringe of black hairs and or course of the abdominal fold. Antenna, head and thorax as in the male; abdomen dark brownish black above.

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