Woolly grass-veneer

''Thaumatopsis pexellus'', the woolly grass-veneer, is a moth in the Crambidae family. It was described by Zeller in 1863. It is found in most of North America. The habitat consists of grasslands.

The wingspan is 21–32 mm. The forewings are yellowish grey with a whitish line, the outer half bounded above by a thicker dark brown line. There is a terminal row of three to five dark dots. Adults are on wing from July to early September in most of the range.

The larvae feed on various grasses.