Hello, i found this small moth 2 times (West Sumatra), really similar to M. collina from Borneo :
https://www.projectnoah.org/spottings/13023135

There is 1 species endemic to Sumatra : M. baliochraspedus, but i can't find any documentation about this species so i can't compare with the one i found. The only description of this species is in Heterocera. Collected in Korinchi, West Sumatra, by Messrs. H.C. Robinson and C. Boden Kloss J. Fed. Malay States Mus. 8 (3) : 107-139
But i can't access this publication.

obs 1 Metaemene sp1 obs1.jpg obs 2 metaemene sp1 obs2.jpg

Cheers,
Nad Rimba