132 THE CAUSES WHICH PROPAGATE 



of the abdomen, aud a corresponding straight and sharp ridge 

 on the inner side of the third pair of femora, which he inter- 

 preted as the constituents of an organ of sound. In this he is 

 confirmed by Schjodte, who submitted this minute ridge to a 

 strong side-Hght with a microscopic power of 50 to 100 diams. ; 

 the part having been previously detached and cleansed with 

 solution of caustic potash, when on being adjusted so that the 

 rays should strike along it, this ridge further proved to be 

 striated inwardly, the cross bridges standing in relief from 

 reason of their shadows, " regular, close, and minute, in propor- 

 tion to the size of the insect,^'' and therefore constituting a file 

 as we find it in larger musical beetles, over which the ridge on 

 the femora might play.* Herr Westring has mentioned two 

 other micro-beetles of this group that utter a sound — nameh^ 

 BerosHs laridas, a coleopteron about the size of a grain of sand 

 or pin's head, and the, in this country, rather scarce Sperchus 

 emarginatus , which is scarcely its superior, thus ushering us to 

 the very fount of those passions that fired a Troy and shook 

 the pinnacles of heaven. 



One large black fluvial species of this family, the great 

 Water Beetle {Kjjdrophilus piceus, L.), also stridulates ; the male 

 when touched or held in the hand contracting the abdominal 

 base within its elytra with a sound ('^^crumph '■') like that prodviced 

 by crumpling a cabbage-leaf. The limae are situated beneath 

 the tip of the elytra, half-lunate in shape, wider inwardly, and 

 shagreened — an appearance here arising from contiguous punc- 

 tures; but in the female this structure is somewhat less marked 

 and hairy. 



The common Necropliaga , or Carrion Beetles, are a provision 

 to remove the remnants of the feast of vulture and hyaena, in 

 which they find able co-operation on the part of various flies. 

 But Nature hastening in her phases, and imperious of speedy 

 assimilation, commissions them to consign to it their thousand 

 eggs, and then (the species being often, as the blue fly, vivipar- 

 ous) insect and grub work rapidly and simultaneously, while the 

 tainted organism shrivels in the sun. The genus Necrophorus 

 (Plate III., Fig 6), contains some kinds wholly black and some 



* The arched limas are bent back in Heteroccrus sericans and intermedins, 

 Fhy sites aureolas and Augijtes hispidus. 



