The length of the forewings (either of the two front wings of a four-winged insect) of a Tridrepana subadelpha, which are pale yellow with a brown crescent patch under the apex, with a brownish-black ovate spot inside, is about 13 mm.
Tridrepana subadelpha is a moth in the family Drepanidae. The length of the forewings is about 13 mm. The forewings are pale yellow with a brown crescent patch under the apex, with a brownish-black ovate spot inside. The discal spot and mid-cell spot are greyish brown, and there is a white strip ringed with brown, as well as two big round greyish-brown patches near the lower angle of the cell, each with a dark brown ovate spot inside. 
