The biggest butterflies my research turned up were:

The Queen Alexandra’s birdwing butterfly. The females are brown and white. The males are black and blue Queen A . They live in Papua New Guinea. Females are larger.

The Goliath birdwing lives in the same area. Females are brown, white and yellow. Males are black, green, and yellow Goliath B . Females are bigger.

The African giant swallowtail is orange, brown, and black. Males and females look similar African G .

Were one of these the butterfly you had in mind?

This butterfly is known as the Queen Alexandra Birdwing! The females wings are brown and white, and the males are the more brightly colored green/blue. The reason the males are more brightly colored, and this is true for a lot of species in the world, is that the males usually have to attract the female! The color helps them do that.

According to National Geographic, the largest known butterfly is Queen Alexandra's birdwing, in Papa New Guinea. Females have black-lined wings with a greenish color while males have brown and yellow wings. Both male and female genders of this butterfly have a black upper body and a yellow lower body.

Wow! Thanks! Here's a picture of the largest butterfly - it's sort of black with blue/green/yellow patches :
largest butterfly .

The world's largest butterfly is the Queen Alexandra's Birdwing. It has a wingspan of 12 inches and is native to Papua New Guinea. The world's smallest butterfly is the Western Pygmy Blue. It has a wingspan of 0.5 to 0.75 inch and is native to the western U.S.

What is the smallest and largest butterfly/moth found at Reiman Gardens?
here

The world's largest butterfly is Ornithoptera alexandrae, or the Queen Alexandra's birdwing, and it has a wingspan of almost ten inches. The boys and girls of this species look quite different: the girls are orange and brown, while the boys are green and black . The girls are also a little bit bigger than the boys, although even the boys are pretty good sized.