Type species: chrysolineata
Typically, Berta species
are medium emerald green with a wing pattern where white fasciae have become
broad and broken up into small patches, giving almost a chequered appearance.
The forewing discal spot is usually ringed white. In B. annulifera Warren
the white fasciae are still narrow, entire, so the derivation of the pattern in
more strongly marked species can be appreciated. The postmedials are set
relatively close to the margin, and there are often additional white patches in
the medial area. The male antennae are of the untidy, adpressed bipectinate type
as in Jodis. The hindwing is tailed weakly at M3, and there is usually an
additional angle at M1. The venation of the forewing has the end of the cell
rather broad, oblique.
The male genitalia,
setation of the third sternite (Fig 399) and ornamentation of the eighth are as
in Jodis. The female genitalia are also similar.
Distinction of the genus
from Jodis therefore rests on the distinctive facies and biangular tail
shape. In Jodis the facies and tail shape are rather plesiomorphic within
the Hemitheiti so it may be that Berta is merely a distinctive,
well-defined subgroup within a broader "Jodis" concept.
The larva of the type
species is described below. Several plant families are recorded as hosts.
The genus is restricted
to the Indo-Australian tropics, with its greatest diversity in S.E. Asia. There
are ten or more species in Borneo, and also numerous species in Sulawesi.
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