34 HEREDITY AND SEX 



Let us follow Montgomery's careful observations on 

 Phidippus purpuratus. The male spun a small web 

 of threads from the floor to one side of his cage at an 

 angle of 45°. ''Four minutes later he deposited a 

 minute drop of sperm on it, barely visible to the naked 

 eye ; then extending his body over the web reached his 

 palpi downwards and backwards, applying them al- 

 ternately against the drop ; the palpal organs were 

 pressed, not against the free surface of the drop, but 

 against the other side of the web." Later, a minute 

 drop of sperm is found sticking to the apex of one of the 

 palpi. In 1678 Lister had shown that the male applies 

 his palpi to the genital aperture of the female ; but not 

 until 1843 was it found by Menge that the palpi carry 

 the sperm drop. 



In man, courtship may be an involved affair. Much 

 of our literature revolves about this period, while paint- 

 ing and sculpture take physical beauty as their theme. 

 Unsatiated with the natural differences that distinguish 

 the sexes, man adds personal adornment which reaches 

 its climax in the period of courtship, and leaves a 

 lasting impression on the costuming of the sexes. 

 Nowhere in the animal kingdom do we find such a 

 mighty display ; and . clothes as ornaments excel the 

 most elaborate developments of secondary sexual char- 

 acters of creatures lower in the scale. 



I have sketched in briefest outline some of the gen- 

 eral and more familiar aspects of sex and the evolution 

 of the sexes. In the chapters that follow we shall take 

 up in greater detail many of the problems that have 

 been only touched upon here. 



