Chap. X. COLEOPTEEA. 385 



myself observed, a tapping noise artificially made ; and 

 Mr. Doubelday informs me that lie has twice or thrice 

 observed a female ticking, 75 and in the course of an hour 

 or two has found her united with a male, and on one 

 occasion surrounded by several males. Finally, it seems 

 probable that the two sexes of many kinds of beetles 

 were at first enabled to find each other by the slight 

 shuffling noise produced by the rubbing together of the 

 adjoining parts of their hard bodies ; and that as the 

 males or females which made the greatest noise suc- 

 ceeded best in finding partners, the rugosities on various 

 parts of their bodies were gradually developed by means 

 of sexual selection into true stridulating organs. 



" 5 Mr. Doubleday informs me that " the noise is produced by the 

 " insect raising itself on its legs as high as it can, and then striking its 

 " thorax five or six times, in rapid succession, against the substance 

 " upon which it is sitting." For references on this subject see Landois, 

 ' Zeitschrift fiir wissen. Zoolog.' B. xvii. s. 131. Olivier says (as quoted 

 by Kirby and Spence, 'Introduct.' vol. ii. p. 395) that the female of 

 Pimelia striata produces a rather loud sound by striking her abdomen 

 against any hard substance, "and that the male, obedient to this call, 



soon attends her and they pair." 



.. 



VOL. I. 2 c 



