Nacaduba hermus, the pale four-line blue,[1][2] is a species of lycaenid butterfly found in Indomalayan realm.

On the underside of the forewing there are transverse bands of the ground colour defined by very fine white lines as follows: The hindwing has transverse bands of the ground colour enclosed and defined as on the forewing by short slender lunular lines of white as follows: Interspace 1 has two minute geminate (paired) black subterminal spots, interspace 2 with one large round black similar spot crowned inwardly with ochraceous and irrorated outwardly with a few metallic blue scales; a very slender terminal white line not extended to the apex and an anteciliary dark line.

[3] Antennae black, shafts minutely ringed with white; head, thorax, and abdomen dark brown; beneath: the palpi fringed with black hairs, thorax fuscous, abdomen dull white.

The forewings and hindwings have anteciliary black lines as in the male, within which on the forewing is an obscure transverse subterminal series of black spots; on the hindwing a very slender terminal white line, a subterminal row of black spots and a postdiscal series of white lunules, the spots decreasing in size and the lunules obsolescent anteriorly.

[3] Nepal, Sikkim; the Western Ghats; Sri Lanka; Assam; Myanmar (Tenasserim); the Andamans.