XXII 



it is true, that certain influences of light can modify the colour of many pupas ; 

 but the different species are not equally susceptible to it and sometimes not 

 at all. So it is probable that the normal coloration which always exists, cannot 

 take its origin from this cause ; also in cases where the said influence cannot 

 ver)' well exist, the pupas are coloured. In some chrj^salides, as in those of 

 the European Papilio Machaon l. there exists colour-dimorphism and this 

 indicates perhaps a stage of transition, in which the original colour changes 

 into another, and thus a process of colour-evolution. Not long ago Cecil 

 Floersheim published in Ent Rec. XVII : „Soine notes on the earlier stages of 

 Papilio Machaon, pattiaclarly ivitli regard to the colour-dhiiorphhm in its pupa." 

 The observations which it contains are very important, so far as they also again 

 show that mimicr)- does not act a part in it; as the author, however, is ignorant 

 of the phenomenon of colour-evolution, he does not know how to explain the 

 colour-dimorphism of those pupas and confines himself to the supposition that 

 it must be of a mechanical nature. The treatment of the Papilionidae and 

 Danaidae, families, in which this colour-dimorphism of the pupas especially 

 occurs, will give me the opportunity to discuss this matter. As to the Pieridae 

 this phenomenon only reveals itself in the unequal increase of the black spots 

 on some pupas. 



Every time the opportunity occurs, I intend, when speaking of the Rhopalo- 

 cera of Java, to indicate how, in my opinion, the form or the colour of a 

 species may be explained, and to make this clear by the necessary figures. 

 As to the so-called influences of mimicry and the process of atrophy of the 

 hind-wings, the treatise concerning the Papilionidae will principally give me the 

 opportunity to do so, as to the colour-evolution, that of the Pieridae. The great 

 number of figures and descriptions of the early stages, which for the greater 

 part have arisen from researches, first made by me, will also be of great use. 



He, who is acquainted with the biological phenomenon of the colour-evolution 

 and who, therefore, understands the nature of the colour-difference in apparently 

 closely related Lepidoptera, can, of course, not agree with the mania of to-day 

 to form new species only because of such differences of colour. There where 

 indeed distincdy separated races or so called subspecies ^) exist, a trinominal 



') The term subspecies has been very much used of late )-ears, I cannot agree with this use 

 because this word intimates a sub-division of the species, which however, is not the case, as is 

 it meant to distinguish different forms only in which the same species occurs. When these 

 progenerate separated from each other, they form races. It is also objectionable to indicate 

 them as geographical or local races, because the separation is often geographical, but not always 

 so; and also becau.se this name gives too much the impression as if various local influences are 

 the cause of the difference of forms, for— though such influences are, indeed, sometimes met 



