the forms of female. At the same time the general arrangement of the darker markings is on the whole similar to that in the _hippocoon_ and in the _trophonius_ form. _Trimeni_ is found on the Kikuyu Escarpment, near Mt Kenia, along with the four mimicking forms. Continental Africa, south of the equator, has produced no female similar to the male. But in Abyssinia is found another state of things. Here, so far as is known, occur three forms, all tailed, of which one is similar in general colour and pattern to the male, while the other two, _niavioides_ and _ruspina_[16], resemble respectively a tailed _hippocoon_ and a tailed _trophonius_. Lastly we have to record that _Papilio dardanus_ is also found as the geographical race _humbloti_ on Comoro Island, and as _meriones_ on Madagascar. In both forms the females are tailed, and resemble the males. From this long series of facts it is concluded that the male of _P. dardanus_ represents the original form of both sexes. On the islands of Comoro and Madagascar this state of things still survives. But it is supposed that on the African continent existed enemies which persecuted the species more than on the islands {33} and encouraged the development of mimetic forms in the female. The original female still lingers in Abyssinia though it is now accompanied by the two mimetic forms _niavioides_ and _ruspina_. Over the rest of the area occupied by _dardanus_ the females are always tailless and, with the exception of _trimeni_ and _dionysus_, wonderfully close mimics. _Trimeni_, the intermediate form, provides the clue to the way in which the mimetic females have been derived from the male, viz. by the prolongation across the fore wing of the dark costal bar already found in the females of the Madagascar and Abyssinian races, by the deepening of the dark edging to the wings, and by the loss of the tail. Through the gradual accumulation of small variations _trimeni_ came from the male-like female, and by further gradual accumulation of small favourable variations the mimetic forms came from _trimeni_. South of the equator the male-like form and the intermediate _trimeni_ have disappeared owing to the stringency of selection being greater. Moreover the likeness of mimic to model is closer than in the north, a further proof of the greater stringency of natural selection in these parts. Such in brief is the explanation in terms of mimicry of the remarkable and complex case of _dardanus_.