Mature larvae can attain a length of 125 mm .
Mature larvae occur in green , yellow and brownish - grey colour forms ( most commonly grey ) , with oblique body stripes and a prickly tail horn that is curled at the extreme tip .
Mature larvae can attain a length of 125 mm and occur in green , yellow and brownish - grey colour forms ( most commonly grey ) , with oblique body stripes and a prickly tail horn that is curled at the extreme tip .