Curetis thetis, the Indian sunbeam,[1][2][3] is a species of lycaenid or red butterfly found in Indomalayan realm.

[1] The butterfly occurs in Peninsular India, south of the Himalayas, but not in the desert tracts or in areas with a scanty rainfall; parts of Assam; Saurashtra; Bengal, Sylhet onto Myanmar.

[4] Upperside: forewing dark brownish black; a large medial patch that extends from vein 1 to vein 4, enters the lower half of the cell and extends from base outwards for about two-thirds the length of the wing, white; at the base of the wing this patch is shaded and obscured for a short distance by dusky black.

[4][6] Variety arcuata Moore, differs from typical thetis as follows: Upperside: ground colour similar but of a slightly paler shade in all the specimens I have seen.

[7] The larva has been recorded as feeding on Pongamia glabra, Derris scandens, Abrus precatorius (Leguminosae), Xylia dolabriformis and Heynia trijuga (Meliaceae).

The second segment is quite unmarked; the third to the thirteenth have a subdorsal series of short oblique pale yellowish-green lines between which the ground-colour is paler than the rest of the body; there is a dark green dorsal line; on each side of the ninth segment there is a prominent pure dead-white, somewhat diamond-shaped mark.

"There is a conspicuous heart-shaped pale ochreous mark on the top of the thorax, the pits on it filled in with reddish pigment."