Euthalia telchinia, the blue baron,[1][2] is a species of nymphalid butterfly found in South and Southeast Asia.

Hindwing broadly pear shaped, the costa, apex and termen roundly curved; tornus slightly produced; dorsum arched, slightly emarginate above tornus.

Underside rich fuliginous brown, basal area below the cell of the forewing and basal area of the hindwing with loop-like black markings; cellular area of forewing crossed by five transverse, short, sinuous, black lines; both forewing and hindwing with broad, lunular, very obscure, dark discal broad and postdiscal narrow transverse bands.

[6] The female resembles the female of Tanaecia cocytus but apart from the difference in the shape of the forewing the ground colour on the upperside is a darker brown; there are five not four dingy white discal spots, the upper two and the lower two subequal; the inwardly oblique postdiscal dark band very diffuse and much broader.

The underside is of a much paler ochraceous, but the markings are similar, Antennae, head, thorax and abdomen dark brown in both sexes; beneath in the male pale brownish, in the female ochraceous.