Preferred common name: Dock sawfly or dock false-worm
The green larvae of this sawfly live on various weeds, such as sorrel, dock and willow herb.
Normally, the fully grown larvae gnaw their way into dry plant stems where they pupate, but occasionally they try elsewhere.
When they attack wooden articles in the house they may become a nuisance. Very often they give up gnawing and try elsewhere, leaving a number of half-finished holes in the timber (see p. 117).
It is very often new houses that are subjected to the attacks of these otherwise completely harmless insects. This may be due to the fact that the gardens have not yet been cultivated so that the ground is covered with the various weeds on which the larvae feed.