386 THE ORIGIN OF SPECIES 



an instance of such kinds mocking other insects, though they are 

 mocked; insects cannot easily escape by flight from the larger 

 animals which prey on them; therefore, speaking metaphorically, 

 they are reduced, like most weak creatures, to trickery and dis- 

 simulation. 



It should be observed that the process of imitation probably 

 never commenced between forms widely dissimilar in color. But, 

 starting with species already somewhat like each other, the closest 

 resemblance, if beneficial, could readily be gained by the above 

 means, and if the imitated form was subsequently and gradually 

 modified through any agency, the imitating form would be led 

 along the same track, and thus be altered to almost any extent, so 

 that it might ultimately assume an appearance or coloring wholly 

 unlike that of the other members of the family to which it be- 

 longed. There is, however, some difficulty on this head, for it is 

 necessary to suppose in some cases that ancient members belong- 

 ing to several distinct groups, before they had diverged to their 

 present extent, accidentally resembled a member of another and 

 protected group in a sufficient degree to afford some slight protec- 

 tion, this having given the basis for the subsequent acquisition of 

 the most perfect resemblance. 



ON THE NATURE OF THE AFFINITIES CONNECTING ORGANIC BEINGS 



As the modified descendants of dominant species, belonging to 

 the larger genera, tend to inherit the advantages which made the 

 groups to which they belong large and their parents dominant, 

 they are almost sure to spread widely, and to seize on more and 

 more places in the economy of nature. The larger and more domi- 

 nant groups within each class thus tend to go on increasing in size, 

 and they consequently supplant many smaller and feebler groups. 

 Thus, we can account for the fact that all organisms, recent and 

 extinct, are included under a few great orders and under still 

 fewer classes. As showing how few the higher groups are in num- 

 ber, and how widely they are spread throughout the world, the 

 fact is striking that the discovery of Australia has not added an 

 insect belonging to a new class, and that in the vegetable kingdom, 

 as I learn from Dr. Hooker, it has added only two or three fami- 

 lies of small size. 



In the chapter on geological succession I attempted to show, on 

 the principle of each group having generally diverged much in 

 character during the long-continued process of modification, how 

 it is that the more ancient forms of life often present characters in 



