Chap. XL Summary on Insects. 329 



Sextial selection implies that the more attractive individuals 

 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 the type to 

 which the species belongs ; — and as it is the male which searches 

 eagt-rly for the female, we must suppose that the females 

 habitually or occasionally prefer the more beautiful males, and 

 that these have thus acquired their beauty. That the females 

 in most or all the orders would have the power of rejecting 

 any particular male, is probable from the many singular con- 

 trivances possessed by the males, such as great jaws, adhesive 

 cushions, spines, elongated legs, &c., for seizing the female ; for 

 these contrivances shew that there is some difficulty in the act, 

 so that her concurrence would seem necessary. Judging from 

 what we know of the perceptive powers and affections of 

 various insects, there is no antecedent improbability in sexual 

 selection having come largely into play ; but we have as yet no 

 direct evidence on this head, and some facts are opposed to the 

 belief. Nevertheless, when we see many males pursuing the 

 ^anie female, we can hardly believe that the pairing is left to 

 blind chance — that the female exerts no choice, and is not 

 influenced by the gorgeous colours or other ornaments with 

 which the male is decorated. 



If we admit that the females of the Homoptera and Orthoptera 

 appreciate the musical tones of their male partners, and that the 

 various instruments have been perfected through sexual se- 

 lection, there is little improbability in the females of other 

 insects appreciating beauty in form or colour, and consequently 

 in such characters having been thus gained by the males. But 

 from the circumstance of colour being so, variable, and from its 

 having been so often modified for the sake of protection, it ia 

 difficult to decide in how large a proportion of cases sexual 

 selection has played a part. This is more especially difficult in 

 thoise Orders, such as Orthoptera, Hymenoptera, and Ooleop- 

 tera, in which the two sexes rarely differ much in colour; for 

 we are then left to mere analogy. With the Coleoptera, however, 

 as before remarked, it is in the great Lamellicorn group, placed 

 by some authors at the head of the Order, and in which we 

 sometimes see a mutual attachment between the sexes, that 

 irc find the males of some species possessing weapons for sexual 

 sti'ife, others furnished with wonderful horns, many with stridn- 

 lating organs, and others ornamented with splendid metallic 

 tints. Hence it seems probable that all those characters have 

 been gained through the same means, namely sexual selection. 

 With bultorflios wo have the best evidence, as the males 



