Homeosis in Mylothris sulphurea Aurivillius, 1895

This is a male of Mylothris sulphurea from the remote Gotel mountains of Nigeria, collected by Malcolm Warren during an expedition with his brother Robert Warren, who has been studying butterflies in Nigeria for two years. It will immediately be seen that the hindwing has been imprinted with the entire pattern of the forewing. This very rare phenomenon is known as homeosis. It is the finest example I have seen during forty years of studying African butterflies.