A small moth with 10-11mm wingspan.  The adults are whitish, with grey and black flecks and markings.

The larvae feed on marjoram, or occasionally mint or thyme, in portable Coleophora-like cases made of the plant's calyces fitted inside each other, a new calyx being added as the larva grows. The larva is pale yellow with a brown head and brown marks on the pronotum.

Where marjoram is present; calcareous grasslands 

Adult flies in summer.  Cased larvae can be found on the host plant in summer and autumn

Scattered across England and Wales, mainly coastal

Rarely recorded; limestone areas in Rutland

https://ukmoths.org.uk/species/thiotricha-subocellea/