730 Mr. Gilbert J. Arrow 07i 



those I have described in Bolhoceras, but of much less 

 extent. The author referred to considers the primary 

 function of the spines to be connected with the folding of 

 the wings, but he has traced to them rustling sounds 

 which he believes also to have significance. Probably the 

 first object of these spiwes in all cases was to give strength 

 to the integument without destroying its fiexibility, and 

 whatever other uses they may have acquired it will not 

 be doubted, I think, that in the species of Bolhoceras just 

 mentioned there has been a special adaptation for the 

 purpose of sound-production. In Gcotruiics the dorsal 

 spines are reduced to very small masFes at the extreme 

 margins of the segments, but the observation that in this 

 undeveloped condition they give rise to a sound is of very 

 great interest, showing that they constitute the germ of 

 a musical apparatus whose development might reasonably 

 be anticipated in allied insects devoid of any other 

 instrument for the purpose. 



It is best to await observations of living individuals 

 before attempting to determine the extent to which 

 musical poweis prevail among the numerous species of 

 Bolhoceras. Probably most are dumb or produce only 

 very slight sounds. Although I have only found the 

 definitely localized wing-spines in the species mentioned, 

 there are in others short stout spines distributed over a 

 great part of the wing. In others these are entirely 

 absent. I believe the species of OdooitieiLS, a genus 

 scarcely more entitled to separation from Bolhoceras tlian 

 several forms still included in it, will be found to utter a 

 quite audible sound. The wings of this, of which a rare 

 representative lives in our own country, are exceedingly 

 large in proportion to its small size, and, even though 

 elaborately folded, entirely cover the back. The whole 

 distal half is crowded with short spines which give a 

 smoky colour to the wings. Short conical spines are 

 usually found upon the stouter membrane which occurs 

 at the anterior edge of the wings of Lamellicorn beetles 

 just beyond the point at which folding takes place. These 

 in the Passalidse have been found to take part in the 

 production of sound, and it seems to me likely that in 

 Geotrti'iKS also it is these surfaces rather than the elytra 

 which, in conjunction with the dorsal areas, produce the 

 sound noti( ed by Verhoefif. 



The Geotrupidse are musical also in the larva state, but 



