Wingspan 9-12 mm.
Only separated as a different species from P. myllerana in 1936, the two are very alike in outward appearance, although there are some subtle differences, including the area of white dusting, which extends more than half way across the forewing in P. sehestediana. However, the two species are best identified by genitalia dissection.
The distribution is confused by early records before the species were split, but it is known to occur in southern England as well as parts of Scotland.
The adults fly during the daytime in two generations; in May and again in July and August.
Skullcap (Scutellaria galericulata) and lesser skullcap (S. minor) are the foodplants, the larvae feeding amongst the leaves in a silken web.