I'm not sure this sighting matches. E. sarcitrella. The whitish 'collar' seems more extensive and less distinct than other examples elsewhere. There is no line white dots along the forewing outer margin and the palps seem to be uniform white whereas in E. sarcitrela they have white and black barring (eg sighting 4609507). I was drawn to P. orescoa because of the outher one third of the forewing is darker with a distinct boundary to the rest like in that species.
@donhe and @ibaird the wings were uneven and there is a distinct line where it changes colour. It's a bit hard to tell because of the sunlight and shadow, but I think palps are one colour not barred.
More ploblematic for it being P.orescoa, I think, is the lack of a distinct black edge or 'collar' to the thorax,. See here:- https://www.inaturalist.org/observations/34525833
This mooth does not have a white head and thorax (& shoulders) if you look closely at 2nd shot it has sun shining at an angle from above onto top of it, rest is in shade.
It looks like something like Philobota mucida https://bold-au.hobern.net/specimens.php?taxid=409653 https://inaturalist.ala.org.au/observations?place_id=6744&preferred_place_id=6744&quality_grade=research&taxon_id=703330