Wingspan 6-8 mm.
Distributed mainly in the south-east of England, P. tenerella has been occasionally found elsewhere, probably as an introduction with the foodplant.
The larva creates a narrow mine on the underside of a leaf of hornbeam (Carpinus), which can be confused with other hornbeam feeding species. However, tenerella is the only one likely to emerge with a white ground colour.
The adults fly in two generations, in May then again during July and August.