170 THIRD ANNUAL REPORT OF 



[o] This in nowise alters the fact, however, of the existence of 

 mimicry in Disippus, which Mr. Scudder fully admits. It is, there- 

 fore no argument against Natural Selection having produced such 

 mimicry. Because we are able to explain the principle power work- 

 ing to produce the relative abundance of one species, compared with 

 another that is closely allied, it does not follow that we must also give 

 the varied influences which cause the relative abundance or rarity of 

 other species in other groups! 



The third objector is Mr. A. Murray, who undertakes to show that 

 these mimetic resemblances have nothing to do with Nnaural Selec- 

 tion. * He takes it upon himself to assert that every inch of ground 

 which Mr. Bates has gone over is u mined and unsound" — that the 

 " bad smell has not been observed in North America where similar 

 mimicry occurs"; and that "birds and insects of prey hunt by sight and 

 not by smell." Any one who will take the trouble to carefully read 

 the paper in which these assertions occur, will, I have little doubt- 

 come to the conclusion that it is the author's ground which is "mined 

 and unsound." The second assertion, as I have already shown, is false'? 

 and even if the third is admitted, it does not in the least affect the 

 argument in favor of Natural Selection, because the fact nevertheless 

 remains that some groups do enjoy immunity from the attacks of 

 birds while others do not. The manner in which Mr. Murray would 

 account for this mimicry is by hybridization, and he endeavors to draw a 

 parallel between the phenomenon and hybridization in plants. He car- 

 ries little weight in his arguments, which were in a measure anticipated 

 by Mr. Bates himself, and have since been refuted by Mr. Butler and 

 Mr. Wallace. f He forgets that hybridization cannot play any part 

 in the mimicry of insects to the vegetable kingdom, or to backgrounds 

 generally. It has never been known to occur between insects of dif- 

 ferent Orders, families, or even genera, and produce fertile offspring,! 

 while mimicry does occur even between insects of distinct Orders 5 

 and though he of course supposes the hybridization to have taken 

 place at a very remote date, when the structural characters of the 

 mimickers and mimicked were less specialized, yet had such been 

 the case, these structural characters would not now remain so distinct 

 between them, because it is quite fair to suppose that the hybrids 

 would partake of the characters of each parent. Indeed the assump- 

 tion of the theory is unsupported by facts. He ignores in a measure 

 the great difference in the affinities of species belonging to the natural 

 Orders of plants, and those belonging to the Orders of insects, and 

 depreciates the importance of the latter by comparing the Orders 



Kature III, pp. 5 54-6. 



t Ibid., Ill, p. 105. 



iCases of hybridization even between species of the same genus are very rare, and it, is doubt- 

 ful if the hybrids would ever be fertile ; and as to hybrids between genera I do not think a case 

 has ever been recorded. In 1865 I succeeded in obtaining thorough coitus between a $ Atlacus 

 Cynthia, Hubn., and 2 Attacus recropia, Linn., hut for some reason the eggs resulting from this in- 

 tercourse did not hatch. Last, year [ succeeded in producing an equally thorough coitus between 

 a <$ Attacus cecropia, Linn., and a $ Attacus polyphemus, Linn., but the eggs subsequently deposited 

 by the latter were likewise infertile. 



