Male Rapala iarbus has red-orange upper wings with costal side and distal front wings are dark brown, female is dull copper brown. The underside of the wing is pale gray, having a pale brown post-discal band that is white on the outside. The hind wing has a prominent black spot with an orange crown in space 2, the marginal area at space 1b is covered in bluish color. This species has a white tipped tail at the end of the 2nd vein, white legs and black stripes.
Larva: larvae of Rapala iarbus are yellowish green to reddish green with slanted dorso-lateral patches with white stripes. Its body is covered in short setae.
Pupa: Pupa of Rapala iarbus is reddish brown in color with small black spots, it looks like a lycaenid in general with a longer abdomen.