338 SEXUAL SELECTION. Part II. 



thinks that, as a general rule, it is the male. Both 

 sexes whilst young, as I am informed by the same 

 author, usually resemble each other; and both often 

 undergo great changes in colour during their successive 

 moults before arriving at maturity. In other cases 

 the male alone appears to change colour. Thus the 

 male of the above-mentioned brightly-coloured Spa- 

 rassus at first resembles the female and acquires his 

 peculiar tints only when nearly adult. Spiders are 

 possessed of acute senses, and exhibit much intelli- 

 gence. The females often shew, as is well known, the 

 strongest affection for their eggs, which they carry 

 about enveloped in a silken web. On the whole it 

 appears probable that well-marked differences in colour 

 between the sexes have generally resulted from sexual 

 selection, either on the male or female side. But doubts 

 may be entertained on this head from the extreme 

 variability in colour of some species, for instance of 

 Theridion lineatum, the sexes of which differ when 

 adult ; this great variability indicates that their colours 

 have not been subjected to any form of selection. 



Mr. Black wall does not remember to have seen the 

 males of any species fighting together for the posses- 

 sion of the female. Nor, judging from analogy, is this 

 probable; for the males are generally much smaller 

 than the females, sometimes to an extraordinary de- 

 gree. 14 Had the males been in the habit of fighting 

 together, they would, it is probable, have gradually 



14 Aug. Vinson ('Arane'ides des lies de la Ke'union,' pi. vi. figs. 1 

 and 2) gives a good instance of the small size of the male in Epeira 

 nigra. In this species, as I mny add, the male is testaceous and the 

 female black with legs banded with red. Other even more striking 

 cases of inequality in size between the sexes have been recorded 

 C Quarterly Journal of Science,' 1868, July, p. 429); but I have not seen 

 the original accounts. 



