In 1871 Darwin published The Descent of Man. He had deliberately avoided human evolution in the Origin but that hadnt workedthe whole controversy revolved around the obvious implication for humans and by the time the Descent was published the controversy was largely over. Nevertheless it was an important work because it also dealt with sexual selection. Darwin considered sexual selection a separate mechanism for explaining evolutionary change though it is now regarded as simply an aspect of natural selection. He explained sexual differences such as male antlers and the peacocks tail as the result of differential success in males either competing against other males or being chosen by females and therefore having more offspring. So much of Descent is on sexual selection it is effectively two distinct books. Darwin later explained During many years it has seemed to me highly probable that sexual selection has played an important part in differentiating the races of man When I came to apply this view to man I found it indispensable to treat the whole subject in full detail. Consequently the second part of the present work treating of sexual selection has extended to an inordinate length compared with the first part but this could not be avoided. Later Life Darwin did more than make small edits and corrections to the Origin in his later years. Yet to come were several major works. In 1862 he published On the Various Contrivances by which British and Foreign Orchids are Fertilised by Insects known simply as Orchids. Darwin wrote to John Murray his publisher I think this little volume will do good to the Origin as it will show that I have worked hard at details. In Orchids Darwin applied the principles of natural selection to make a startling prediction. First he described a remarkable flower from Madagascar called Angaecum sesquipedale A whip-like nectary of astonishing length hangs down beneath the labellum. In several flowers sent to me by Mr. Bateman I found the nectaries eleven and half inches long with only the lower inch and a half filled with very sweet nectar. Then he added in Madagascar there must be moths with probosces capable of extension to a length of between ten and eleven inches No such moth was known and Darwin was ridiculed by some scientists for suggesting it existed. But he was proven right. The moth was found and described forty-one years later in 1903. It had a wingspan of 13 to 15cm and a proboscis 25cm long 10 inches. It was a new subspecies and it was named Xanthopan morgani praedictathe predicted moth. 37 Xanthopan morganii praedicta. The predicted moth.