Description
The Tree Yellow, at a glance, resembles the abundant Eurema species that are found in Singapore. However, on closer inspection, this species is slightly paler and unmarked on the undersides of the wings. Except for a narrow black forewing border, the Tree Yellow is a plain lemon yellow throughout.
It is usually found within the nature reserves and is not found outside the protection of the forests, unlike the Eurema species. The female of this species can be distinguished by a dentate projection in the black border at vein 4 of the forewing, and a generally paler colour.

Habitat & Habits
The Tree Yellow is relatively common, and can be observed in many locations in the nature reserves. Contrary to what Corbet & Pendlebury describes in their book, Butterflies of the Malay Peninsula 4th edition, page 100, this species has often been observed "puddling" i.e. feeding on moist spots on muddy paths - and occasionally, up to 3 or more individuals are seen at the same spot.

Other Observations
To be detailed.

Early Stages
Refer to the ButterflyCircle's blog article - LIfe History of the Tree Yellow.

Further Reading
To be detailed.