Combined photo taken on Sept 6, 2014 shows butterflies presented during a butterfly carnival held in the scenic spot of Iron Tower in Kaifeng, central China's Henan province. [Photo by Li An/xinhuanet.com]

A visitor takes photo of a butterfly during a butterfly carnival held in the scenic spot of Iron Tower in Kaifeng, central China's Henan province, Sept 6, 2014. [Photo by Li An/xinhuanet.com]

Photo taken on Sept 6, 2014 shows a butterfly presented during a butterfly carnival held in the scenic spot of Iron Tower in Kaifeng, central China's Henan province. [Photo by Li An/xinhuanet.com]

A butterfly rests on the shoulder of a girl in the scenic spot of Iron Tower in Kaifeng, central China's Henan province, Sept 6, 2014. [Photo by Li An/xinhuanet.com]

A visitor takes photos of a butterfly during a butterfly carnival held in the scenic spot of Iron Tower in Kaifeng, central China's Henan province, Sept 6, 2014. [Photo by Li An/xinhuanet.com]