Indigenous to England, Scotland, Wales, and Ireland, and common in England and Wales, less common in Ireland and very rare in Scotland. 
   Found primarily in scrubby grassland and woodland.
    They are fast and erratic fliers, with short flight periods 
   Adults hibernate through cold weather, and can often be seen flying on warm days throughout the year, although they are most common in the spring.    Usually seen in ones or twos, they are never very common, but are quite widespread. 
   By using mimicry and camouflage to avoid predation, they have become known as master of disguise.
   The Brimstone has spread in recent years, primarily in northern England. 
   When it roosts among foliage, the angular shape and the strong veining of their wings closely resembles leaves, also helping it avoid predation.
   It is believed that the word 'butterfly' originates from the yellow color of male Brimstones.
   The wings of the female are very pale green, almost white, males have yellow-green ventral side wings and yellow dorsal side wings.
   The brimstone will probably be the first butterfly you see in spring. 
   Because they excrete a large part of their body fluid in the cold winter, brimstone butterflies can survive in temperatures as low as -20°C.
   They emerge from hibernation as soon as it starts to warm up, but during mid-summer, they enter a second resting phase called summer dormancy. 
   This makes them one of the longest-living butterflies with a lifespan of up to 10 months. 
   Brimstone butterflies have characteristically leaf-like wings; the males are a pale lemon yellow while the females are more of a greenish yellow.