252 The Descent of Man. Part 11 



in a state of nature, fewer female Lepidoptora may reach maturity 

 than males ; and for our special object we are concerned with their 

 relative numbers at maturity, when the sexes are ready to propagate 

 their kind. 



The manner in which the males of certain moths congrpfrate in 

 extraordinary numbers lound a single female, apparently indicates a 

 great excess of males, though this tact may perhaps be accounted for 

 Dy liie earlier emergence of the males from tlieir cocoons. Mr. 

 Stainton informs me that from twelve to twenty males, may often be 

 St en congregated round a female Mlachista rufocinerea. It is well 

 known that if a virgin Lasiocampa quercus or Salurnia earpini 

 be exposed in a cage, vast numbers of males collect round her, and if 

 con lined in a room will even come down the chimney to her. Mr. 

 Uuubleday btlieves that he has seen from fifty to a hundred males of 

 hoih thete species attracted in the course of a single day by a female 

 in confinement. In the Isle of Wight Mr. Trimen exposed a bnx 

 in which a female of the Lasiocampa hid been confined on the 

 previous day, and five males soon endeavoured to gain admittance. 

 In Australia, M. Verreanx, having placed 1he female of a small 

 1-iombyx in a box in his pocket, was followed by a crowd of males, so 

 that about 200 entei'ed the house with him." 



Mr. Doubleday has called my attention to M. Staudinger's '^ list 

 of Lepidoptera, which gives the prices of the males and females of 

 300 species or well-marked varieties of butterflies (Rhopalocera). The 

 prices for both sexes of the very common species are of course the same; 

 but in 114 of the rarer species they differ; the males being in all cases, 

 excepting one, the cheaper. On an average of the prices of the 113 species, 

 the price of the male to that of the female is as 100 to 149 ; and this 

 apparently indicates that inversely the males exceed the females in 

 Ihe same proportion. About 2000 species or varieties of moths 

 (Heterocern) are catalogued, those with wingless females being here 

 excluded on account of the difference in habits between the two sexes : 

 of these 2000 species, 141 differ in price according to tex, the males 

 of 180 being cheaper, and those of only 11 being dearer than the 

 females. The average price of the males of the 130 species, to that of 

 the females, is as lOo to 143. With respect to the butterflies in this 

 priced list, Mr. Doubleday thinks (and no man in England has had 

 more experience), that there is nothing in the habits of the species 

 which can account for the difference in the prices of the two sexes, 

 and that it can be accounted for only by an excess in the number of 

 the males. But I am bound to add that Dr. Staudinger infoims me, 

 that he is himself of a different opinion. He thinks that the less active 

 habits of the females and the earlier emergence of the males will 

 account for his collectors securing a larger number of males than 

 offemales, and consequently for the lower prices of the former. With 

 respect to specimens r. ared from the <;aterpillar-state. Dr. Staudinger 

 believes, as previously state d, that a greater number of females than of 

 males die whilst confined in the cocoons. He adds that with certain 

 species one sex seems to preponderate ovej' the other during certain 

 years. 



Of direct observations on the sexes of Lepidoptera, reared either 



*^ Blaochard, * Metamorphoses, ®^ ' Lcpidopteren - Do'aMfttPB 



Moeurs des Insattes,' 1868, pp. 225- Liste.' Berlin, No. i. 1866. 

 826. 



