CONTENTS 13 



PAET II 

 SEXUAL SELECTION 



CHAPTER Vm 



FRINOIPLGS OF BBXUAL SELEOTIOIT 



Secondary sexual characters — Sexual selection — Manner of action — Excess 

 of males — Polygamy — The male alone generally modified through 

 sexual selection — Eagerness of the male — Tariability of the male — 

 Choice exerted by the female — Sexual compared with natural selec- 

 iion — Inheritance, at corresponding periods of life, at corresponding 

 seasons of the year, and as limited by sex — Belations between the 

 several forms of inheritance — Causes why one sex and the young are 

 not modified through sexual selection — Supplement on the proportional 

 numbers of the two sexes throughout the animal kingdom — The pro- 

 portion of the sexes in relation to natural selection .... 374 



CHAPTER IX 



SEOONDABY SBZUAL 0HABA0TEE3 IN THB LOWER CLASSES OP THE ANIMAL 



KINGDOM 



These characters absent in the lowest classes — Brilliant colors — MoUusca — 

 Annelids — Crustacea, secondary sexual characters strongly developed; 

 dimorphism ; color ; characters not acquired before maturity — Spiders, 

 sexual colors of; atridulation by the males — Myriapoda . . . 344 



CHAPTER X 



BEOONSABT SEXITAL OHABAOIBBS OF INSBOTa 



Diversified structures possessed by the males for seizing the females — 

 DifEerences between the sexes, of vrhioh the meaning is not under- 

 stood — Difference in size between the sexes— Thysanura—Diptera^ 

 Hemiptera — ^Homopiera, musical powers possessed by the males 

 *savage'''imEQ^i?» mnsieal instruments cA the males, much diversl- 

 Curiosity-ImitatiSa'Snacityj colors-Nentoptera. sexual differences , 

 Progressive ImprovemenP"8"ao''y «"* colors-CoIec^rtem, coIots; 

 Abstraction, self-conscious^,' aPPow^Hy «« »» ornament; tetfles; 

 - in God, spiritual agencies, supP""'''"'^***^ • ' ' " '"^ 



