Species within the genus Eurema range from Asia, Africa, Australia, and Oceania, to the Americas. 
At least 71 species are currently known. 
The main differences between the species are:
a) the number of spots in the underside forewing cell, combined with
b) the shape of the upperside forewing black markings and
c) the shape of the apical area markings on the forewing underside. 

Eurema sari (36–42 mm), sometimes also called the Chocolate Grass Yellow, is a butterfly in the family Pieridae. 
It is found in Southeast Asia.
Adults have a distinct solid brown apex on the underside of the forewing which instantly sets it apart from the other Eurema species found in Singapore. 
This species is quite common, and can be found in many locations in the nature reserves as well as in urban areas in Singapore.

This is the subspecies Eurema sari sodalis found in Singapore.

Sungei Buloh Wetland Reserve, Singapore, 25 October 2022