Hello!

"A butterfly is an insect of the order Lepidoptera. Like all
holometabolous insects, butterflies' life cycle consists of four
parts, egg, larva, pupa and adult. Most species are diurnal. The
diverse patterns formed by their brightly coloured wings and their
erratic flight have made butterfly watching a hobby."

for more information:

http://en.wikipedia.org/wiki/Butterfly (totally reliable source)