PROPORTION OF TEE SEXES. 



285 



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

 800 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 the same proportion. About 

 2,000 species or varieties of moths (Heterocera) are catalogued, 

 those with wingless females being here excluded on account 

 of the difference in habits between the two sexes: of these 

 2,000 species, 141 differ in price according to sex, the males of 130 

 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 100 to 143. With respect to the butterflies in this 

 price-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 informs 

 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 of females, and consequently for the lower prices of the 

 former. With respect to specimens reared from the caterpillar 

 state, Dr. Staudinger believes, as previously stated, that a greater 

 number of females than of males die while confined in the cocoons. 

 He adds that with certain species one sex seems to preponderate over 

 the other during certain years. 



Of direct observations on the sexes of Lepidoptera, reared either 

 from eggs or caterpillars, I have received only the few following 

 cases: 



*This naturalist has been so kind as to send me some results from former 

 years, in which the females seemed to preponderate ; but so many of the 

 figures were estimates that I found it impossible to tabulate them. 



