There are many variations of T. helena cerberus. Specimens examined by Haugum & Low (1982-1985) from BMNH, RMNH, Copenhagen Zool. Museum., Treadaway Frankfurt Coll. ..etc. and documented by them:

Male forms:
1. f-cerberus Felder: with median stripe on underside of FW, upperside also distinctly striped, and HW with larger subcostal patch.
2. f-eumagos Jordan 1908: FW without median stripe, or the latter submarginal; the subcostal patch of the HW typically reduced in size.
3. f- no name: HW with full compliment of small black spots.
4. f- no name: HW notably triangular, with outer margin convex instead of concave (samples from Cameron Highlands).
5. f- no name: HW with a black blotch within the subcostal space, a large black spot in the space below, an smaller spots in the remaining spaces(N. India & Thailand).
6. f- no name: Costal-subcostal of HW much extended, the black spots increased in size (Thailand).

Female forms:
1. f-chongkiakwangi Tung 1981: a male like form which largely lack of blacks spots on the HW.
2. f- no name: Pale vien stripes and cell-patch coloured bluish-grey.
3. f- no name: Pale vien stripes and cell-patch coloured yellow or yellow-tan.
4. f- pluto Felder 1864: Pale area of HW coloured with red instead of yellow.

Similarly for T. amphrysus ruficollis (both males and females), many variations too.

Specimen variation occurs partly due to genetic mutations and varying environmental factors(e.g. availability and quality of larval food..), but most important is because of individuals possess different combinations from the selection of genes available to them.

Teo T P

(FW= forewings; HW= hindwings; BMNH= British Museum Natural History; RMNH= Rijksmuseum van Natuurlijke Histoire, Leiden)