THE SEXUAL FORM OF INFLUENCE. i 82 
groups, it will next be in place to consider the way in which each 
method of influence acts and the different forms of action that it 
assumes in producing results under each principle. 
1. The Forms of the Conjunctional Method of each of the Four Principles. 
Producing demarcation of habitudinal Producing intensified divergence in 
groups: habits of groups: 
Conjunctional partition. Conjunchional election. 
Family partition. Sexual election. 
Social partition. Social election. 
Filio-parental election. 
Producing demarcation of racialgroups: Producing intensified divergence in 
racial characters: 
Conjunctional isolation. Conjunctional selection. 
Sexual isolation. Sexual selection. 
Social isolation. Social selection. 
Filio-parental selection. 
The conjunctional method of influence is due to the need of coérdi- 
nation between one sex and the other in the intergenerating group, 
between each member and the othersin an associating group, and 
between the parents and offspring in each family group. 
2. The Sexual Form of Selection, Election, and Isolation. 
Sexual selection is due to the necessity for codrdination between the 
sexual instincts and palpable qualities of the individual of either sex 
and the instincts and palpable qualities of the other sex, in order to 
secure propagation with survival in subsequent generations. It is 
often assumed that in creatures lower than man sexual selection may 
be effective in establishing the normal standards of prowess and dis- 
play in the male sex, but that it avails very little in determining the 
standards of attainment in the female sex. This is in a considerable 
degree true of species in which the male is the party that seeks and 
calls for a mate; but even in these species the answering call of the 
female is often a necessary feature in the attainment of suitable mat- 
ing; and the hen-bird that has lost her voice goes desolate. In some 
species of insects the call for a mate comes from the male, and the part 
‘of the female is to respond by leaving its distant hiding-place and com- 
ing to the male. The methods of one such species are described in 
my paper on Intensive Segregation, reproduced in Appendix II of this 
volume. 
Sexual election is due to the necessity for codrdination between the 
acquired habits and standards of the individual of either sex and 
the sexual instincts, as well as the acquired habits and standards of 
