Cloudless Sulphur (Phoebis sennae)
This large sulphur is almost entirely yellow, particularly the male. The female has black borders around the forewing and some darker patches on the underside of its wings. Both sexes have spots in the middle of the underside of each wing, although they are much more pronounced on the female. On the female, white spots are circled in dark, with a pair of spots on the hindwing. On the male, the hindwing has a single white spot and the forewing has a small pinkish spot.
I have primarily seen this species feeding on flowering bushes. The underside of the male great southern white (Ascia monuste) may look similar when resting, but it lacks the spots on the underside, and is clearly distinguished in flight because the upper side is white rather than yellow.