428 THE DESCENT OF MAN 



protection; and it is almost certain that she has sometimes 

 been made brilliant, so as to imitate other protected species 

 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 protection. So it is in some instances when both 

 are brightly colored, for they thus imitate protected species, 

 or resemble surroundiag 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 throughout 

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

 differ widely in color from the females, while others differ 

 slightly or not at all, with intermediate gradations connect- 

 ing 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 Orthop- 

 tera have generally been transferred in a rudimentary, or 

 even in a nearly perfect condition, to the females; yet not 

 sufficiently perfect to be of any use. It is also an interest- 

 ing fact, as bearing on sexual selection, that the stridulating 

 organs of certain male Orthoptera are not fully developed 

 until the last moult; and that the colors of certain male 

 dragon-flies are not fully developed until some little time 

 after their emergence from the pupal state, and when they 

 are ready to breed. 



Sexual selection implies that the more attractive individ- 

 uals are preferred by the opposite sex; and as with insects, 

 when the sexes differ, it is the male which, with some rare 

 exceptions, is the more ornamented, and departs more from 



