Contents. xiii 



PAQB 



N imeioiis puinls of resemblance in body and mind between the 

 most distinct races of man — The state of man when he tirst 

 spread over the earth — Each race not descended from a single 

 [ttir — The extinction of races — The formation of races^Tlie 

 t ffcots of crossing — Slight influence of the direct action of the 

 conditions of life — Slight or no influenue of natural selection — 

 fi^^sual selection ..,.,,. 166 



PART II. 

 SEXUAL SELECTION. 



CHAPTER VIIL 



PuisciPLES OF Sexual Seleotios. 



Secondary sexual characters — Sexual selection — Manner of action 

 — Excess of males — Polygamy — The male alone genernlly 

 modified throufjh sexual selection — Eagerness of the mule — 

 Variability of the mali — Choice exeited by the female — Sfxual 

 compared with natural selection — Inheritance at corresponding 

 periods of life, at corresponding seasons of the year, and as 

 limited by sex — Relations between the several forms of inheri- 

 tance — Causes why one sex and the young are not modifiid 

 through sexual selection — Supplement on the proportional num- 

 bers of the two sexes througliout the animal kingdom — The 

 proportion of ihe stxes in relation to natural selection . . 207 



CHAPTER IX. 



Secondary Sexual Characters in the Loweu Classes of 

 THE Animal Kingdom. 



These i haraoters absent in the lowest classes — Brilliant colours — 

 MoUusca— Annelids— Crustacea, secondary sexual characters 

 strongly developtd; dimorph'sm; colour; oliaracters not ac- 

 quired before maturity— Spiders, sexual colours of; stridulation 

 by tlie malts — Myriapoda ...... 2(1(1 



CHAPTER X. 



Seoondaky Sexual Characters of Insects. 



Diversified structures possessed by the males for seizing the 

 females— Diiferences between the sexes, of which the mean- 

 ing is not unders'ood— Difference in size bt-tween the sexes — 

 Tliysaiiuru^-Dip era — Hemipti ra — Homoptora, musical powers 



