A quite large butterfly, 3 1/2" - 4" in size, and probably the best known. It is the only butterfly that migrates on a regular basis as do certain birds. But, since the journey is so very long from their summering areas throughout North America to the Sierra Madre in Mexico or to southern California, no single individual makes the entire trip. It lays its eggs on milkweed plants which are now under general attack and its wintering sites in Mexico and California are threatened also.

What a pretty stamp sheet.