Phalaris arundincea, het Twiske; head and pronotum, sternum
two left prolegs, anal prolegs
Bland, (1996a) describes the larva as being yellowish white with a brown head; prothoracic plate consisting of several brownish sclerites; according to Traugott-Olsen & Schmidt-Nielsen (1977a) the ventral side of the larva is dark brown.
The larvae, when in the mine, have fairly deep intersegmental constrictions. This must be because they are squeezed a bit – outside the mine they are much more terete.