You can see why it is called the Map (Fr. Carte géographique).
This stylish black and white colourway is its summer outfit, known as form prorsa or the summer morph.
Individuals that emerge in July look like this.
The black and tan colourway, form levana or spring morph, is reserved for those who overwinter in their chrysalis and emerge in April. They are always much less abundant than their summer siblings.
The summer morph tends to be slightly larger in the thorax and wing and more abundant. This and the colouring may be connected to the fact that it is this generation that migrates. The larger size and different proportions of the summer morph give these butterflies a lower wing loading, suggesting that they are more mobile.