574 Dr. F. A. Dixey's reply to Mr. G. A. K. Marshall 



that any case of this kind may really carry conviction as a 

 proof of diaposematism it is necessary to show that the 

 reciprocal character which the model is claimed to have 

 acquired from the mimic must be one that is abnormal in 

 the genus of the model and its allies." On this I would 

 observe that if Mr. Marshall will look again at my paper 

 from which he quotes (Trans. Ent. Soc. Lond., 1894, pp. 

 296-298), he will see that I do not claim that the exist- 

 ence of the red basal patches in Heliconius has been 

 *' acquired from the mimic." On the contrary, I am in that 

 passage at pains to show that there already exists in 

 Heliconius material in the shape of red basal markings for 

 the aposeme that becomes especially conspicuous in those 

 species which enter into mimetic relation with red-spotted 

 Pierines. Hence his enumeration of red-spotted Heliconii 

 is beside the mark, for he has not met my assertion that 

 the spots are especially distinct and characteristic in these 

 mimetic species. My view was and is that the Pierines 

 have contributed to the special appearance presented by 

 the spots in certain species ; not that they are actually 

 responsible for the origin of those marks. I fear I cannot 

 agree that a character such as this, if reciprocally adopted, 

 must be " abnormal in the genus of the model and its 

 allies," for in most cases there will be found already exist- 

 ing, as might be expected, some basis for the assimilative 

 process to work on. 



While the Heliconii are under consideration, it may not 

 be amiss to remark on the great plasticity exhibited by 

 this genus, so far as concerns its colour-patterns. This is 

 exemplified by the large number of species which, as 

 Mr. Marshall says, " have been drawn away in mimicry of 

 the great Melinsea-Mcchanitis associatioa," and still more 

 by the completeness with which members of one of the 

 two great groups into which the genus falls have become 

 assimilated in aspect to species belonging to the other.* 

 Mr. Marshall himself suggests that the absence of red 

 spots in the Meliniea-\\ke Heliconii may be due to mimicry, 

 which shows that in his view this feature of the Heliconine 

 pattern is not resistent to mimetic influence. As regards 

 the Pierines, there is no reasonable doubt that the red 

 basal aposeme in Delias has impressed itself not only upon 

 Prioneris but also on Chalcosid moths (see Shelford, Proc. 



* See Riffarth and Stichel, in the " Thierreicli," 1905 ; also W. J. 

 Kaye, Proc. Ent. Soc. Lond., 1907, pp. xiv-xvi, 



