MORPHOLOGY
External characteristics
Male
Forewing length (mm): 18 - 22 (Otsuka, Kazuhisa, 2001), 22 (Kirton, 2018). Wingspan (mm): 37 (Braby, 2004), 40 (Feltwell, 1993).
Forewings: The species can always be recognized by the large reddish apical spot on the forewing upper side. The forewing upper side has a black margin, this black border is serrate and vertical (D'Abrera, 1982). The forewing has a pointed apex and a black coloured border. There are two black coloured cellspots. The upper side wing surface is more or less black dusted and the ground-colour is glossy yellow. The sex brand is broad (Yata and Morishita, 1979). Hindwings The black coloured border on the hindwing is narrower than the one on the forewing (Yata and Morishita, 1979).
Female Wingspan (mm):40 (Braby, 2004; Feltwell, 1993).
The female lacks the whitish gloss on the hindwing underside (Yata and Morishita, 1979).
Subspecies and variation
There are nearly 40 subspecies; D'Abrera (D'Abrera, 1982) describes only two. Sumatran males of ssp. latilimbata are nearly twice the size of males of the other subspecies (D'Abrera, 1982). Seventeen subspecies are described, but according to Yata and Morishita (Yata and Morishita, 1979) ssp. dentyris and ssp. maroensis may belong to Eurema alitha. There is seasonal and geographical variation. The subspecies found in Celebes and the Sula Islands have a well developed black border along the hind margin of the forewing upper side. The dry season form of this species has a more angular apex and less developed black borders, which are often reduced to spot on the hindwing; the forewing underside has better developed black spots. In the lower latitudes, the differences between the dry season and wet season forms are becoming less clear. The female of ssp. satellitica has more heavily black dusting on the upper side wing surface and this subspecies is smaller than the nominate species. The submarginal series of spots are enlarged in ssp. tamiathis. Ssp. pylos has the best developed black border along the hind margin of the forewing and the females upper side wing surface is almost completely black (Yata and Morishita, 1979).