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pointed out on page V of the Introduction and further on page 1 1 , the process 

 of colour-evolution often takes place more slowly than on the upper-side, with 

 the result that more relicts of the original colour can remain. 



That red is there then mixed with black which has also been developed 

 there and shows itself as a spot, the size of which is not always the same; 

 where this remnant is still ver)' large, so many red scales have often been 

 preserved, that the spot is still distinctly reddish. In advanced evolution we 

 see in some individuals the red disappear entirely and then of that spot there 

 only remains an indistinct black remnant ; in many specimens the red turns 

 into a yellowish brown and then the spot grows gradually smaller. Sometimes 

 there are several suchlike spots, but much smaller, on the under-side; and we 

 do now and then see besides the rather big reddish brown spot of the hind-wings, 

 still another rather big one on the fore-wings. In the said large spot a pecuhar figure 

 is often formed at the outward extremity of the discoidal cell, generally consisting 

 of two joined rings in the shape of an 8 and with a pearly centre; on the 

 under-side of the fore-wings this also takes place; here, however, the figure 

 consists of one ring only and has no metallic hue. Evidently it is nothing but 

 the figure already mentioned when speaking of C. Scylla L., the development 

 of which may easily be traced in this species as a transformation of the spots 

 of pigment in that place into one or two united rings, a formation which the 

 pigment has a great tendency to adopt, especially where it surrounds callous 

 spots or other accumulations of pigment, and which causes the ocellar markings 

 or eye-spots which are so common on many butterflies. When the evolution 

 proceeds this figure gets smaller and at last nothing remains of it but a small 

 round spot at the same place in each wing, which spot sometimes as a last 

 relic, retains the red colour; showing hereby that, according to the rule in 

 the process of colour-evolution the black pigment is gradually disappearing 

 again, so that only a few scales of the original relic have been preserved, which 

 have still retained the original colour. Often, however, this remnant is still 

 blackish or of a distinctly reddish brown, viz. black mixed with red. 



Both, the said figure, as well as those red relics, also exist in many other 

 Pieridae; among the European species the former is f. i. present in Colias 

 Hyale L., the latter in Gonopteryx Rhamni L. But what the significance of 

 those relics there is, generally remains a mystery to entomologists; not until 

 we study the many forms of C. Pomona F., knowing the phenomenon of 

 colour-evolution, can we understand their phylogenesis and thereby their nature. 

 Such a study clearly shows that the occurrence of particular patterns of colour 

 or accumulations of pigment on the wings is by no means dependent on chance 

 and is not caused by exterior influences either, but that it is the utterance of 



