100 THE STUDY OF ANIMAL LIFE CHAP. 



courtship of spiders, which is less ideal. We have 

 selected some illustrations from an account of the court- 

 ship of spiders by George W. and Elizabeth G. Peckham. 



According to these observers, " there is no evidence that the 

 male spiders possess greater vital activity ; on the contrary, it is 



FIG. 28. A SPECIES OF GELASIMUS. 

 (Drawn from a specimen.) 



This genus of crabs is widely represented on tropical shores. The 

 male is marked by an enormous exaggeration of one of the forceps or 

 chelae, usually the right. In the female the two chela? are small and of 

 the same size. 



The exaggerated forceps has probably several uses. It may be used 

 by the male to close the door of the burrow when he and his mate are 

 safely within. It may be used in fighting with other males. Alcock 

 observed in Indian Ocean species that the large chela is bright red and 

 that the males brandish it about before the females as if to excite their 

 admiration. The long stalks of the eyes will be noticed. 



the female that is the more active and pugnacious of the two. 

 There is no relation in either sex between development of colour 

 and activity. The Lycosidse, which are the most active of all 

 spiders, have the least colour-development, while the sedentary 

 orb-weavers show the most brilliant hues. In the numerous cases 

 where the male differs from the female by brighter colours and 

 ornamental appendages, these adornments are not only so placed 



