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large number of different forms, it proceeds much slower in this species ; only 

 on the upper-side of the fore-wings of some $ from Celebes the basal area is 

 shaded with much black, reminding us of the quantity of black which occurs on 

 the upper-side of many 9 of C. Pomona F. from the same island, though 

 in 9 of other regions this is not the case. In Java the process in this species 

 only reveals itself in the paler or darker shade of the yellow, especially on the 

 under-side, and in the number and size of the brown spots there, which are 

 distinctly relics. Among the c/ these spots are generally insignificant; at least 

 never so strongly developed as in some $ ; there are also $, however, in which 

 they are almost entirely wanting. Their nature is of exactly the same 

 character as in Terias Hecabe L. and they have also the same colour. In 

 specimens, in which they are strongly developed, they sometimes form a 

 figure in the shape of an 8 at the outward extremity of the discoidal cell on 

 the under-side of both wings, (PI. Ill fig. ^b) ; evidently the same figure as is 

 common in several species of Colias and which will be treated of when speaking 

 of C. Pomona F. We then also sometimes see, however, the same figure, 

 but somewhat smaller or paler, as a black pattern at the same place on the 

 upper-side of the fore-wings (PI. Ill fig. ^d) ; something which seems to me not 

 unimportant from a biological point of view. It is indeed evident that we are 

 placed here before the same fact, observed among many butterflies, that some- 

 times the colour and pattern on one side of a wing repeats itself, though paler, 

 on the other side. Though this fact, however, as far as I know, has only 

 been observed as a repetition of colour and pattern from the upper-side to 

 the under-side, the contrary takes place here. 



Indeed the circumstance that this repetition on the upper-side often does 

 not occur at all, and if it does, only in a less developed form than on the 

 under-side, clearly shows that, if here, at least, it is a matter of repetition, it 

 must take place from the lower to the upper-side in the case in question. The 

 reason of this phenomenon is not yet known; and as far as I know, at least, 

 it has not yet been seriously studied. My observation, just mentioned, may 

 perhaps contribute a little to its being done. We might consider the supposition 

 that that peculiar arrangement of the pigment on the under-side is connected 

 with the particularly strong development of the veins on the wings in that place, 

 and then we might further suppose that the same cause will also lead to the 

 same result on the upper-side in respect to the pigment there. But for a general 

 explanation of the phenomenon, this supposition will not do. It seems more 

 admissible to suppose here some correlative influence; among caterpillars also 

 some repetitions of colour and pattern occur, which, undoubtedly, must be 

 of a correlative nature and in which the repetition is always a little more feeble 



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