I believe the image above rather closely matches Superagnia fuchsi Breuning, 1968, which I have from Borneo and is also known from Sumatra. The size of the specimen is in agreement. Stegenagapanthia nivalis from Borneo is about 10 mm shorter. The third antennal segment of Superagnia is longer than the 3rd antennal segment of Stegenagapanthia. The specimen from Cameron Highlands and S. fuchsi have very similar bicolored terminal antennal segments, which are rather difficult to see in my specimen.