Stenoma iostalacta is a moth of the Depressariidae family. It is found in Peru. The wingspan is about 24 mm. The forewings are pale grey with the costal edge pale ochreous. The markings are light ferruginous-brownish, darker towards the costa and partially on the edges. There is a dot near the base in the middle and a triangular patch extending on the dorsum from near the base to the middle, its apex confluent with a spot on the costa at one-third, its posterior edge with a projection in the disc. A transverse-oval spot represents the second discal stigma and there is a triangular spot on the middle of the costa, where a shade, strongly excurved beyond the second discal stigma, runs to the dorsum at three-fourths, its extremity produced each way on the dorsal edge. There is a larger triang