A large caddisfly with a forewing length of 18 to 26 mm. In the female the two sections of the dark central wing bar usually well separated by a pale area, although this is not a reliable way of separating the species from P. grandis.

Ponds, lakes, canals and slow rivers.

Flight period May to July.

Fairly frequent in most of Britain, less common in Scotland.

Infrequent in Leicestershire and Rutland.