134 DARWINISM 



cases by downy seeds to be wafted through the air, or by 

 hooked or sticky seed-vessels to be carried away, attached to 

 skin, wool, or feathers. 



Here, then, we have an enormous extension of the region of 

 utility in the vegetable kingdom, and one, moreover, which 

 includes almost all the specific characters of plants. For the 

 species of plants are usually characterised either by differences 

 in the form, size, and colour of the flowers, or of the fruits ; 

 or, by peculiarities in the shape, size, dentation, or arrange- 

 ment of the leaves ; or by peculiarities in the spines, hairs, or 

 down with which various parts of the plant are clothed. In 

 the case of plants it must certainly be admitted that " specific " 

 characters are pre-eminently adaptive ; and though there may 

 be some which are not so, yet all those referred to by Darwin 

 as having been adduced by various botanists as useless, either 

 pertain to genera or higher groups, or are found in some 

 plants of a species only — that is, are individual variations not 

 specific characters. 



In the case of animals, the most recent wide extension of 

 the sphere of utility has been in the matter of their colours 

 and markings. It was of course always known that certain 

 creatures gained protection by their resemblance to their 

 normal surroundings, as in the case of white arctic animals, 

 the yellow or brown tints of those living in deserts, and the 

 green hues of many birds and insects surrounded by tropical 

 vegetation. But of late years these cases have been greatly 

 increased both in number and variety, especially in regard to 

 those which closely imitate special objects among which they 

 live ; and there are other kinds of coloration Avhich long 

 appeared to have no use. Large numbers of animals, more 

 especially insects, are gaudily coloured, either with vivid hues 

 or with striking patterns, so as to be very easily seen. Now 

 it has been found, that in almost all these cases the creatures 

 possess some special quality Avhich prevents their being 

 attacked by the enemies of their kind whenever the 

 peculiarity is known ; and the brilliant or conspicuous colours 

 or markings serve as a warning or signal flag against attack. 

 Large numbers of insects thus coloured are nauseous and 

 inedible; others, like wasps and bees, have stings; others are 

 too hard to be eaten by small birds ; while snakes with 



