Parnassius is a genus of northern circumpolar and montane (alpine and Himalayan) butterflies usually known as Apollos or snow Apollos. They can vary in colour and form significantly based on their altitude. They also show an adaptation to high altitudes called altitudinal melanism. They show dark bodies and darkened colouration at the wingbase which helps them warm faster using the sun. Although classified under the swallowtail butterfly family, none of the Parnassius species possesses tails.