Species within the genus Eurema (Grass Yellows) range from Asia, Africa, Australia, and Oceania, to the Americas.
The Grass Yellows are generally weak flyers, fluttering low around bushes and flowers.
At least 71 species are currently known, eight of which are found in tropical Africa.
They are generally difficult to tell apart and what makes it even more difficult is that the sexes often differ slightly and there are different seasonal forms (wet and dry season forms).
The main differences between the species are:
a) the number of black spots on the underside of the forewing, combined with
b) the shape of the (apical) black markings on the upperside of the forewing and
c) the shape of the apical area markings on the underside of the forewing. 

There are 7 species within the genus Eurema in Uganda; Eurema hecabe, senegalensis, brigitta, floricola, hapale, desjardinsii and mandarinula.
The main differences between them are the following: 
1. Eurema hecabe is generally distinguished from other members of the genus by the very irregular inner margin of the dark apical band on the upperside of the forewing (evenly rounded in most other species except the much paler Eurema hapale).
2. Eurema senegalensis is a common forest butterfly that usually flies higher up than the closely-related Eurema hecabe.
3. Eurema brigitta differs from other species of Eurema in possessing more elongated forewings. Also, the inner margin of the dark apical band on the forewing upperside is more or less evenly rounded (not very irregular as in Eurema hecabe). Furthermore, the underside of the hindwings in both sexes are covered with (sometimes very pronounced) small dark spots which give the wings a rather spotted appearance, as compared to the other species in the genus.
4. Eurema floricola looks very similar to Eurema hecabe but in Eurema floricola the hindwing margin has distinct spots at the end of each vein; they are not joined to one another and never form a band. In Eurema hecabe, the hindwing margin has a continuous black margin (wet season) or it has spots (normally dry season) which are flattened indicating the remnants of the black margin. 
5. Eurema hapale has an affinity for swamps and flooded areas.
6. Eurema desjardinsii is distinguished from other members of the genus by the "elbowed" hindwing (two 45 angles in de hindwing).
7. Eurema mandarinula usually occurs in grassy areas in and around forest at altitudes above 1,400m.

First 4 photos: Lake Mburo National Park, Uganda, 17 January 2025
5th photo: Bigodi area, Kibale National Park, Uganda, 25 January 2025