208 Animal Life and Intelligence. 



fairly be held to have a value which he does not admit. 

 For if preferential mating is a priori probable, such display 

 may be regarded as the outcome of this mode of selection. 

 At the same time, it may be 'freely admitted that more 

 observations are required. In a recent paper, " On Sexual 

 Selection in Spiders of the Family A ttida," * by George W. 

 and Elizabeth G. Peckham, a full, not to say elaborate, 

 description is given of the courtship, as they regard it, of 

 spiders. The " love-dances " and the display of special 

 adornments are described in detail. And the observers, 

 as the result, be it remembered, of long and patient investi- 

 gation and systematic study, come to the conclusion that 

 female spiders exercise selective choice in their mates. 

 And courtship must be a serious matter for spiders, for if 

 they fail to please, they run a very serious risk of being 

 eaten by the object of their attentions. Some years ago I 

 watched, on the Cape Flats, near Capetown, the courtship 

 of a large spider (I do not know the species). In this case 

 the antics were strange, and, to me, amusing; but they 

 seemed to have no effect on the female spider, who merely 

 watched him. Once or twice she darted forward towards 

 him, but he, not liking, perhaps, the gleam in her eyes, 

 retreated hastily. Eventually she seemed to chase him off 

 the field. 



We must remember how difficult it is to obtain really 

 satisfactory evidence of mating preferences in animals. In 

 most cases we must watch the animals undisturbed, and 

 very rarely can we have an opportunity of determining 

 whether one particular female selects her mate out of her 

 various suitors. We watch the courtship in this, that, or 

 the other case. In some we see that it is successful; in 

 others that it is unsuccessful. How can we be sure that 

 in the one case it was through fully attaining, in the other 

 through failing to reach, the standard of taste ? And yet 

 it 4s evidence of this sort that Mr. Wallace demands. After 

 noting the rejection by the hen of male birds which had 

 lost their ornamental plumage, he says, " Such cases do 



* Natural History Society of Wisconsin, vol. i. (1889). 



