SEXUAL SELECTION 403 



nmny bulitorflies and of some moUis; and it maybe asked, 

 we thoir oolors and tHvorsilied patterns the result of the 

 direct action o£ tho physical coiuUtious to which those 

 insects hiivo boon exposed, without any benefit being thus 

 dorivod? Or have suooessive variations been aoouniuhited 

 and doUuMuiiiod as a protection, or lor some unknown pur- 

 [loso, or tilial. one sox may be attractive to tlio otlior? And, 

 again, what is the moaulug of the oolors being widely dillor- 

 ent in tho males and females of certain species, and alike in 

 tho two soxos of otbor species of the same genus? Before 

 attempting to answer those questions a body of facts must 

 be given. 



With our beautiful English butterflii-s, the admiral, pea- 

 cork, and painted lady (Yanessic), as well as many others, 

 the sexes are alike. This is also the case with the magnill- 

 cent Heliconida\ and most of the D.uiaidra in tlie tropics. 

 But in certain other tropical groups, and in some of our 

 English butterflies, as tho purple empen)r, orange-tip, etc. 

 {Apatuni iris and Anthoc/ian'g cardaminea), the sexes diflfer 

 either greatly or slightly in color. No language suffices to 

 describe the sj>lendor of the males of some tropical species. 

 Even within the same genus we often find spooies presenting 

 extraordinaiy diU'erenoes between the sexes, while others 

 bavo their scxos closely alike. Thus in the South Ameri- 

 can genus Epicalia, Mr. Bates, to whom 1 am iiulobted for 

 most of the following facta, and for looking over this whole 

 discussion, informs me that he knows twelve species the two 

 Boxes of which haunt the same stations (and this is not al- 

 ways tho case with butterflies), and whicli, therefore, cannot 

 have been differently affected by external conditions.' lu 

 nine of these twelve spooies the males rank among the most 

 brilliant of all butterflies, and differ so greatly from the 

 oompamtivoly plain females that they were formerly placed 

 iu distii»ct gonor.a. The females of these nine species i"e- 



» Sm also Mr. Bates's papor In "Proo. Knt, Soo. of PlilladelpliK" 1866. 

 p. a08. Also Mr. WiUlnoo on Uio ssmuo subjoot, in rt>gtu-d to D'^dema, in 

 "Trausnot, Kutomolog. Soo. of London, " 18G9, p. 818. 



