Can be mistaken for :
Clouded Yellow and
Pale Clouded Yellow butterflies, which are similar in colour.
Superficial resemblance to : A
Large White butterfly when in flight, but at close quartwrs can be distinguished from it by the hooked tip of the wings and the absence of black spots. Like a leaf, it also has small brown spots.
The Brimstone butterfly derives its name from the pale yellow colouring of the upper side of the wings, which is likened to sulfur (or brimstone). The underside is a very pale green. Lives for up to 12 months but flies only between June and September and then again in Spring after a winters hibernation. When resting always folds its wings up.