162 THIRD ANNUAL REPORT OF 



beautiful colored figures, in the highest style of art, both of the 

 species that mimic and of those that are mimicked; and no one that 

 looks at those figures with an unprejudiced eye can believe for a mo- 

 ment that the resemblance is merely accidental. 



Even the practiced eye of the entomologist is sometimes deceived 

 by these close resemblances, and to illustrate, I cannot do better than 

 to quote Mr. Bates's own language : 



These imitative resemblances, of which hundreds of instances 

 could be cited, are full of interest, and till us with the greater aston- 

 ishment the closer we investigate them ; for some show a minute and 

 palpably intentional likeness which is perfectly staggering. I have 

 found that those features of the portrait are most attended to by na- 

 ture, which produce the most effective deception when the insects are 

 seen in nature. The faithfulness of the resemblance, in many cases, 

 is not so striking when they are seen in the cabinet. Although I had 

 • daily practice in insect-collecting for many years, and was always on 

 mv guard, I was constantly deceived by them when in the woods, (p. 

 •507). 



Mr. Bates accounts for these singular cases of mimicry by sup- 

 posing that, ages and ages ago, certain individuals of this plainly- 

 dressed and much persecuted Pieris family happened to vary slightly- 

 so as to resemble slightly some species or other belonging to the gaily- 

 dressed and unpalatable Danais family ; that, in consequence of this 

 slight resemblance, they were sometimes mistaken for their more for- 

 tunate compatriots by cannibal animals, which would otherwise have 

 preyed upon them forthwith; and consequently that they survived 

 long enough to propagate their species, while almost all the individuals 

 that had not varied in this particular manner perished prematurely 

 by a violent death. Now, we know that, in the language of breeders 

 and stock-raisers, "like produces like," which is what naturalists ex- 

 press by the well-known term of the " Law of Inheritance." Hence 

 the descendents of this primordial race of imitative butterflies would 

 naturally, most of them, vary in the same manner as did their ances- 

 tors from the normal type ; and some of them would probably vary in 

 a still more marked manner and in the same direction. These last in- 

 dividuals, as they would bear a still closer resemblance to the unpal- 

 atable butterflies, would of course stand a still better chance of sur- 

 viving and propagating their species, in the course of that great 

 Struggle for Existence, which we see going on all around us, not only 

 among the inferior animals, but among the human species itself. By 

 the perpetual repetition of this process, during indefinite ages, that 

 perfect imitation of the imitated butterfly would at length be formed, 

 which at first view appears so utterly inexplicable. And when it had 

 once been formed, the very same process that originally formed it 

 would afterwards keep it up to the standard of perfection. For all in- 

 dividuals, that varied in a backward direction towards the primordial 

 type, would be more liable than the rest to be devoured in early life 

 by cannibals, and would therefore be less likely than the rest to pro- 

 pagate their own image in succeeding generations. The whole pro- 



