'On taking it out of my net and opening the glorious wings, my heart began to beat violently … so great was the excitement.'
Alfred Russel Wallace
Part of Wallace's inspiration for the theory of evolution came from the huge variation he witnessed among the insects, birds and other animals he collected on his travels. Many of the 126,000 specimens he collected in the Malay Archipelago are now in the Museum.
This magnificent butterfly, known as Wallace's golden birdwing butterfly (Ornithoptera croesus), is one of the most famous insects Wallace discovered. He caught it on the Indonesian island of Bacan in 1859, during his eight-year expedition around the Malay Archipelago.
Wallace's understanding of these creatures also led him to formulate the earliest modern definition of species (now known as the biological species concept) in an important paper he wrote about the swallowtail butterflies of the Malay Archipelago: 'Species are merely those strongly marked races or local forms which, when in contact, do not intermix, and [are] incapable of producing a fertile hybrid offspring.'