Common in oak woodland and areas with scattered trees throughout Britain, as far north as Aberdeenshire; common in the south-east but rare in the west and north of its range; its apparent absence from much of the Midlands and central and southern Wales may be due to under-recording (MBGBI Vol 2). In Hampshire and on the Isle of Wight more common than
C. alchimiella. Wingspan 10-13 mm. Easily confused with
C. alchimiella, from which it can only safely be separated by dissection of the genitalia; both feed on oak, but
C. alchimiella is probably univoltine with a protracted emergence period, while
C. robustella is bivoltine. Larva mines leaves of Oak, subsequently living within a leaf-fold, over-wintering as a pupa.