MIMICRY AND PROTECTIVE RESEMBLANCE. 715 



by the suine mc;ins (tlie survival of the l)e8t mocker), whether the object 

 imitated be animal, vegetable or mineral ; the actual outcome is indeed 

 vastly more surprising in some cases than in others; in some "perfectly 

 staggering" as Bates says, but though there be to all appearances a "pal- 

 pably intentional likeness," there is found to be no intention in the case so 

 far as mocker and mocked are concerned ; but the result of a natural se- 

 lection against which neither could even strive, and of which neither was 

 ever conscious.* The process has been a long one, so that in the case of 

 parastatic mimicry, as that form which involves the copying of one's fel- 

 lows might be termed (or if one prefers an English term — neighborly 

 mimicry), we may readily presume far less difference between mocker and 

 mocked when the mimicry between them first began, than now exists 

 between the mocked and the normal relatives of the mocker. It is argued, 

 indeed, with ofreat show of reason, that as tlie resemblance jjrew stronsfcr 

 the birds became more sharp-sighted, which reflected again on the mimicry, 

 and that thus the final departure from the normal type was intensified ; 

 but this assumption is not necessary. 



So far we have only referred to the first illustrations of mimicry given 

 by Bates, presenting the simplest forms though not the least striking, 

 involving as they do the widest departure of mimetic butterflies from their 

 normal type. Let us glance briefly at some other points. 



A new element enters when we find that neighborly mimicry is some- 

 times confined to a single sex of a butterfly ; that is to say, one sex is of the 

 normal color of its allies, while the opposite sex departs widely therefrom, 

 and is found to resemble closely another and a nauseous butterfly of the 

 same region. Now, as mimicry is clearly only a protective device, or 

 rather outcome, we should naturally inquire whether either sex was more 

 in need of protection than the other from those foes against which mimiciy 

 could avail anything. Plainly, it would be the female, since were she 

 lost before oviposition just so many eggs are lost with her ; and besides 

 this her heavier, more sluggish flight — a necessity from her burden of eggs 

 — makes her an easier prey to insectivorous creatures, against which 

 mimicry is aimed. Accordingly we find numerous instances in which 

 the female is mimetic and the male normal. Probably they are far 

 more numerous than we imagine and that many of the exceedingly com- 

 mon diflx^rences between the sexes which since Darwin's day we have been 

 wont to set down to sexual selection are to be attributed to something of 

 this nature. But there is no known case of neighborly mimicry confined 

 to the male sex. On the other hand some of the most vivid and striking 

 examples of mimicry are to be found confined to the females. There is 

 one example brought forward by Trimen which is the most siu-prising yet 



* "Imitation" and 'Mniniicry" l)Otli imply compel us to use tigurativc speech; we have 

 intention; l)ut the limits of our language no word to express unconscious mimicry. 



