Butterfly's mouth belongs to a biological classification called siphonage, just like a long straw, which is used to reach into stamens to suck nectar, usually rolled up and collected in the chin.

Because the mouthparts (that is, the mouth) of the straw type must be elongated to penetrate the stamens, it takes a long time to suck the nectar in the depths of the stamens more conveniently, so the mouth of the butterfly becomes longer and longer.

However, such a long straw-like mouth, knowing that it would be in the way in normal flight, rolled up the long straw, rolled it into a circle and put it under the chin. Take it out when you use it and put it back when you don't use it.

Extended data:

There are about 20,000 recorded butterfly species in the world, and there are 2 153 species in China. In LEPIDOPTERA 158 family, butterflies have 18 family. South America has the largest number of butterflies in the Amazon River basin, followed by Southeast Asia.

The most beautiful and ornamental butterflies in the world are mostly found in South America, Brazil, Peru and other countries. Most of the internationally protected species are distributed in Southeast Asia, such as Indonesia, Papua New Guinea and other countries.

Different humidity and humidity environments and different plant communities have been formed in the same area and at different altitudes, and many different butterfly populations have been formed accordingly.