No. 519] THE COURTSHIP OF ARANEADS 171 



have rather to consider their value to the species, what is 

 their use, and the factors which have served to perpetuate 

 them. 



In the first place it will be convenient to name categor- 

 ically the main classes of secondary sexual characters 

 found in animals in general, and second to discuss the 

 significance of those found in araneads. 



Plate (1908) has furnished a useful tabulation of sec- 

 ondary sexual characters, devised mainly to show "what 

 an enormous morphological field is comprised in this 

 term." The following arrangement of such characters is 

 simpler than his, though as comprehensive, and will be 

 more convenient for our present discussion. 



1. Weapons employed by males in their combats with 

 one another. 



2. Characters used for sexual recognition and sexual 

 stimulation. 



3. Characters of more immediate value in ensuring 

 approximation of the sexes and copulation. 



4. Characters of value in provision for and nurture of 

 the progeny. 



5. Characters due to habitudinal differences of the 



sexes. 



6. Characters of value in protecting a particular sex 

 against other species. 



We may next determine how these six main groups of 

 characters are represented in spiders. 



1. The weapons employed by males in their fighting for 

 the possession of females are readily explained, as Darwin 

 did in the first part of his theory of sexual selection, as 

 being perpetuated by a natural selection between males. 



Such direct combats between males do not appear- to 

 occur among spiders, neither do the males possess pecul- 

 iar weapons, unless peculiarly modified ehelicera may be 

 considered as weapons. Mature males when placed to- 

 gether will frequently fight, but the Peckhams (1889) in 

 describing this in the case of an Ictus conclude that the 

 battles are probably sham affairs, rarely resulting disas- 

 trously, and "gotten up for the purpose of displaying 



