Chap. IX.] SPIDERS. 329 



females, sometimes to an extraordinary degree. 14 Had 

 the males been in the habit of fighting together, they 

 would, it is probable, have gradually acquired greater 

 size and strength. Mr. Blackwall has sometimes seen 

 two or more males on the same web with a single female ; 

 but their courtship is too tedious and prolonged an affair 

 to be easily observed. The male is extremely cautious in 

 making his advances, as the female carries her coyness to 

 a dangerous pitch. De Geer saw a male that " in the 

 midst of his preparatory caresses was seized by the object 

 of his attentions, enveloped by her in a web and then de- 

 voured, a sight which, as he adds, filled him with horror 

 and indignation." 15 



Westring has made the interesting discovery that the 

 males of several species of Theridion 16 have the power of 

 making a stridulating sound (like that made by many 

 beetles and other insects, but feebler), while the females 

 are quite mute. The apparatus consists of a serrated ridge 

 at the base of the abdomen, against which the hard hinder 

 part of the thorax is rubbed ; and of this structure not a 

 trace could be detected in the females. From the analogy 

 of the Orthoptera and Homoptera, to be described in the 

 next chapter, we may feel almost sure that the stridulation 

 serves, as Westring remarks, either to call or to excite 



14 Aug. Vinson (' Araneides des lies de la Reunion,' pi. vi. figs. 1 and 

 2) gives a good instance of the small size of the male Epeira nigra. In 

 this species, as I may add, the male is testaceous and the female black 

 with legs banded with red. Other even more striking cases of inequality 

 in size between the sexes have been recorded (' Quarterly Journal of 

 Science,' 1868, July, p. 429); but I have not seen the original accounts. 



15 Kirby and Spence, c Introduction to Entomology,' vol. i. 1818, p. 

 280. 



16 Theridion (Asagena, Sund.) serratipes, 4-punctatum et guttatum ; 

 see Westring, in Kroyer, 'Naturhist. Tidskrift,' vol. iv. 1842-1843, p. 

 349 ; and vol. ii. 1846-1849, p. 342. See, also, for other species, ' Ara- 

 neae Svecicae,' p. 184. 



15 



