Butterflies of Sri Lanka

Small Grass Yellow
Eurema brigitta rubella, Wallace

Small Grass Yellow

Description
A small, yellow butterfly with a wingspan of 26-40 mm. The seasonal forms of this butterfly vary greatly and grade perfectly into one another. The line between the black and yellow area of the upper side of the forewing is wavy and looks like the knuckles of one's hand. The basal area is dusted with fine black scales and is more extensive in the female than in the male. The cell on the forewing is devoid of any markings.

Typical wet season form.

The apex of the forewing is rounded. On the upper side, the ridges of the 'knuckles' are more flattened, and the black bands on both wings are very wide, uniform and continue to the tornus. On the underside forewing, there is sometimes a black streak that extends from the costa near the apex to vein 4.

Typical dry season form.

The apex of the forewing is very pointed and the ridges of the 'knuckles' are very pronounced. The black band on the hind wing is very jagged and prominent at the apex, but turns into small triangular black areas from the end of the veins 5 to 2 - very unlike the dry season form or the Spotless Grass Yellow. On the underside of the forewing, there is often a pink border below the costa, which the wet season form always lacks. The dry season form is rarer and is always seen at higher altitudes from January to March, the coldest times of the year.

Similar species
Spotless Grass Yellow. More information

Status, distribution and habitat
It occurs commonly in the grasslands of the central hills from 500 to 6000 feet elevation. It has also been recorded from the low country wet zone in the Galle district.

Habits
Very similar to the Common Grass Yellow.

Early stages
Larval host plants: Cassia klenii and Cassia multijuga.

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