182 MISCELLANEOUS OBJECTIONS TO 1TIE [Chap. VII. 



But in all the foregoing cases the insects in their original state 

 no doubt presented some rude and accidental resemblance to an 

 object commonly found in the stations frequented by them. Nor 

 is this at all improbable, considering the almost infinite number of 

 surrounding objects and the diversity in form and colour of the 

 hosts of insects -which exist. As some rude resemblance is neces- 

 sary for the first start, we can understand how it is that the larger 

 and higher animals do not (with the exception, as far as I know, of 

 one fish) resemble for the sake of protection special objects, but 

 only the surface which commonly surrounds them, and this chiefly 

 in colour. Assuming that an insect originally happened to resemble 

 in some degree a dead twig or a decayed leaf, and that it varied 

 slightly in many ways, then all the variations which rendered the 

 insect at all more like any such object, and thus favoured its escape, 

 would be preserved, whilst other variations would be neglected and 

 ultimately lost ; or, if they rendered the insect at all less like the 

 imitated object, they would be eliminated. There would indeed be 

 force in Mr. Mivart's objection, if we were to attempt to account 

 for the above resemblances, independently of natural selection, 

 through mere fluctuating variability ; but as the case stands there 

 is none. 



Nor can I see any force in Mr. Mivart's difficulty with respect to 

 " the last touches of perfection in the mimicry ;" as in the case 

 given by Mr. Wallace, of a walking-stick insect (Ceroxylus 

 laceratus), which resembles "a stick grown over by a creeping 

 moss or jungermannia." So close was this resemblance, that a 

 native Dyak maintained that the foliaceous excrescences were really 

 moss. Insects are preyed on by birds and other enemies, whose 

 sight is probably sharper than ours, and every grade in resemblance 

 which aided an insect to escape notice or detection, would tend 

 towards its preservation ; and the more perfect the resemblance so 

 much the better for the insect. Considering the nature of the differ- 

 ences between the species in the group which includes the above 

 Ceroxylus, there is nothing improbable in this insect having varied 

 in the irregularities on its surface, and in these .having become more 

 or Jess green-coloured ; for in every group the characters which 

 differ in the several species are the most apt to vary, whilst the 

 generic characters, or those common to all the species, are the most 

 constant. 



The Greenland whale is one of the most wonderful animals in the 

 world, and the baleen, or whale-bone, one of its greatest pecu- 

 liarities. The baleen consists of a row, on each side, of the nppei 



