SUMMARY ON INSECTS. 325 



It is also an interesting fact, as bearing on sexual selection, that 

 the stridulating organs of certain male Orthoptera are not fully 

 developed until the last moult; and thUt 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 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 

 eagerly for the female, we must suppose that the females habitual- 

 ly 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 contrivances possessed 

 by the males, such as great jaws, adhesive cushions, spines, elon- 

 gated legs, &c., for seizing the female; for these contrivances 

 show that there is some difliculty in the act, so that her concur- 

 rence 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 same 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 colors 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 selec- 

 tion, there is little improbability in the females of other insects 

 appreciating beauty in form or color, and consequently in such 

 characters having been thus gained by the males. But from the 

 circumstance of color being so variable, and from its having been 

 so often modified for the sake of protection, it is dilfloult to decide 

 in how large a proportion of cases sexual selection has played 

 a part. This is more especially diflicult in those Orders, such as 

 Orthoptera, Hymenoptera, and Coleoptera, in which the two 

 sexes rarely differ much in color; 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 we iind the males of some 

 species possessing weapons for sexual strife, others furnished 

 with wonderful horns, many with stridulating organs, and others 

 ornamented with splendid metallic tints. Hence it seems prob- 



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