Polyura arja is a butterfly belonging to the Rajahs and Nawabs group, the Charaxinae subfamily of the Brush Footed family.
   They can be found in northeast India, (Sikkim to Assam), Burma, Thailand and Indochina.
   The outer edge of their forewings is concave and the hind wings show two short blue tails.

   The dorsal side of the wings is brown with a broad white or anteriorly pale green band from the inner edge of the fore wing to the costal edge of the hindwings, one or two small white spots at the apex of the forewings and a continuous row of white or pale yellow spots running along the outer submargin of the hindwings.

   The ventral side of the wings is lighter brown with a quite similar pattern.

   Their bodies are dark brown.

   * As members of the Brush Footed (Nymphalidae) family, they use their pair of shorter front legs for food tasting, and their two pairs of longer rear legs for propulsion.