390 Darwin, and after Darwin. 



because it is the one which has been published most 

 recently, and partly because it is of particular interest 

 as occurring so low down in the zoological scale. I 

 am indebted to the kindness of Mr. and Mrs. Peckham 

 for permission to reproduce these few selected drawings 

 from their very admirable work, which is published by 

 the Natural History Society of Wisconsin, U.S. It is 

 evident at a glance that all these elaborate, and to our 

 eyes ludicrous, performances are more suggestive of 

 incitation than of any "other imaginable purpose. And 

 this view of the matter is strongly corroborated by 

 the fact that it is the most brightly coloured parts of 

 the male spiders which are most obtruded upon the 

 notice of the female by these peculiar attitudes in 

 just the same way as is invariably the case in the 

 analogous phenomena of courtship among birds, 

 insects, &c. 



But so great is the mass of material which Darwin 

 has collected in proof of all the points mentioned in 

 the foregoing paragraph, that to attempt anything 

 in the way of an epitome would really be to damage 

 its evidential force. Therefore I deem it best simply 

 to refer to it as it stands in his Descent of Man, 

 concluding, as he concludes, " This surprising uni- 

 formity in the laws regulating the differences between 

 the sexes in so many and such widely separated 

 classes is intelligible if we admit the action throughout 

 all the higher divisions of the animal kingdom of one 

 common cause, namely, sexual selection " ; while, as 

 he might well have added, it is difficult to imagine 

 that all the largerclasses of facts which an admission of 

 this common cause serves to explain, can ever admit 

 of being rendered intelligible by any other theory, 



