Scythris arachnodes is a moth of the family Scythrididae. It is found on the Canary Islands.[1]
The wingspan is 7–10 mm. The forewings are black, with a few greyish white scales at the base and two greyish white transverse bands. The hindwings are dark leaden grey.[2]
The larvae probably feed on lichens on the surfaces of rocks. They feed from within a web.