324 THE DESCENT OF MAN. 



been in leading to modifications which sometimes, as with the 

 Homoptera, relate to important parts of the organization. 



From the reasons assigned in the last chapter, it is probable 

 that the great horns possessed by the males of many Lamelll- 

 corn, and some other beetles, have been acquired as ornaments. 

 From the small size of insects, we are apt to undervalue their 

 appearance. If we could imagine a male Chalcosoma (fig. 16), 

 with its polished bronzed coat of mail, and its vast complex 

 horns, magnified to the size of a horse, or even of a dog, it would 

 be one of the most imposing animals in the world. 



The coloring of insects is a complex and obscure subject. 

 When the male differs slightly from the female, and neither are 

 brilliantly-colored, it is probable that the sexes have varied 

 in a slightly different manner, and that the variations have been 

 transmitted by each sex to the same, without any benefit or evil 

 thus accruing. When the male is brilliantly-colored and differs 

 conspicuously from the female, as with some dragon-flies and 

 many butterflies, it is probable that he owes his colors to sexual 

 selection; whilst the female has retained a primordial or very 

 ancient type of coloring, slightly modifled by the agencies before 

 explained. But in some cases the female has apparently been 

 made obscure by variations transmitted to her alone, as a means 

 of direct protection; and it is almost certain that she has some- 

 times been made brilliant, so as to imitate other protected spe- 

 cies inhabiting the same district. When the sexes resemble each 

 other and both are obscurely colored, there is no doubt that they 

 have been in a multitude of cases so colored for the sake of pro- 

 tection. So it is in some instances when both are brightly-col- 

 ored, for they thus imitate protected species, or resemble sur- 

 rounding objects such as flowers; or they give notice to their 

 enemies that they are unpalatable. In other cases in which the 

 sexes resemble each other and are both brilliant, especially when 

 the colors are arranged for display, we may conclude that they 

 have been gained by the male sex as an attraction, and have been 

 transferred to the female. We are more especially led to this 

 conclusion whenever the same type of coloration prevails through- 

 out a whole group, and we find that the males of some species 

 differ widely in color from the females, whilst others differ 

 slightly or not at all, with intermediate gradations connecting 

 these extreme states. 



In the same manner as bright colors have often been partially 

 transferred from the males to the females, so it has been with 

 the extraordinary horns of many Lamellicorn and some other 

 beetles. So again, the sound-producing organs proper to the 

 males of the Homoptera and Orthoptera have generally been 

 transferred in a rudimentary, or even in a nearly perfect condi- 

 tion, to the females; yet not sufficiently perfect to be of any use. 



