COLEOPTERA. 303 



tions, in the same manner as birds use their voices for many pur- 

 poses besides singing to their mates. The great Chiasognathus 

 stridulates in anger or defiance; many species do the same from 

 distress or fear, if held so that they cannot escape; by striking the 

 hollow stems of trees in the Canary Islands, Messrs. Wollaston 

 and Crotch were able to discover the presence of beetles belonging 

 to the genus Acalles by their stridulation. Lastly, the male Ateu- 

 chus stridulates to encourage the female in her work, and from 

 distress when she is removed.™ Some naturalists believe that 

 beetles make this noise to frighten away their enemies; but I can- 

 not think that a quadruped or bird, able to devour a large beetle, 

 would be frightened by so slight a sound. The belief that the 

 stridulation serves as a sexual call is supported by the fact that 

 death-ticks (Anobium tessellatum) are v^rell known to ansv/er each 

 other's ticking, and, as I have myself observed, a tapping noise 

 artificially made. Mr. Doubleday also informs me that he has 

 sometimes observed a female ticking,"" and in an hour or two after- 

 wards has found her united with a male, and on one occasion 

 surrounded by several males. Finally, it is 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 hard parts of their bodies; and that as 

 those males or females which made the greatest noise succeeded 

 best in finding partners, rugosities on various parts of their bodies 

 were gradually developed by means of sexual selection into true 

 stridulating organs. 



™ M. P. cle la Brulerie, as quoted In 'Journal of Travel,' A. Murray, 

 vol. i. 1S68, p. 135. 



8" According to Mr. Doubleday, "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 fur wissen. Zoolog.' B. xvii. s. 131. Oliver says (as quotefl 

 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." 



