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 floricola (sometimes also called Malagasy Grass Yellow) is found in Sierra Leone, Ivory Coast, Ghana, Nigeria, the Democratic Republic of Congo, Burundi, Kenya, Tanzania, Zambia and on Madagascar, the Comoros, Mauritius, Réunion and the Seychelles.
This is the subspecies Eurema floricola floricola which occurs on Madagascar and in eastern Tanzania.
This is a male. 

Dr. David Lees from the Department of Zoology of the University of Cambridge, United Kingdom, helped me identify this species.
I met David in Madagascar in January 2014 during his research work in Andasibe-Mantadia NP and had the pleasure to spent a few days together.
David has extensive field research experience in Madagascar and is considered the leading expert on Madagascar butterflies.

Andasibe-Mantadia National Park, Madagascar, 13 January 2014