SONGS WITHOUT WORDS. 187 



approach more clearly to the region of " hums " and droning, and 

 leave that of specialised sounds, such as we have been metaphorically 

 hearing in the cicadas. To pass from the latter insects to the beetles, 

 bees, flies, and their neighbours, appears to be a transition almost as 

 wide as that between the articulate language or arithmetic of culture, 

 and the scanty vocabulary of the savage or the primitive mathematics 

 of the tribe who can count ten as represented on their fingers and 

 toes, but ask in amazement why there should be more things in the 

 world. In the beetles the sound-producing organ is comparable to a 

 kind of " rasp " which moves upon an adjoining surface. The site of 

 the organ in question varies in different beetles. In some the rasps 

 are situated on the upper surface of one or two of the tail- segments, 

 and are rubbed against the hinder edges of the wing-covers. Some- 

 times the rasp is placed quite at the tip of the tail ; and in some 

 well-known beetles (such as the weevils) the rasps may be borne on 

 the wing-covers and may produce the stridulating sound by rubbing 

 against the edges of the joints of the tail. Amongst the sounds pro- 

 duced by beetles, the weird noise of the death-watch (Anobium) 

 stands pre-eminent. The sound produced by these beetles resembles 

 the ticking of a watch, and they may be made to respond by placing 

 a watch close by their habitats. The female death-watches are known 

 to tick in response to the sounds of the male insects. The noise is 

 produced apparently by the insect raising itself on its legs and by its 

 striking its chest against the adjoining wood. Thus the simple ex- 

 planation of an insect call explains away the superstition expressed 

 in Gay's line : 



The solemn death-watch clicked the hour she died. 



Butterflies and moths are known occasionally to produce sounds, : 

 which proceed in one or two cases at least from a drum- like membrane 

 analogous to that seen in cicada. Mr. Darwin, indeed, mentions that 

 one species (Ageronia feronia) "makes a noise like that produced by 

 a spring catch, which can be heard at the distance of several yards." 

 Amongst the bees, wasps, and other so-called Hymenopterous insects, 

 the production of the humming noise forms a fact of interest in the 

 history of the race. And one or two species possess a power of 

 emitting sounds of more definite nature, which correspond to the 

 " stridulation " of the grasshoppers and their kind. But it is a well- 

 known and at the same time interesting fact, that bees are known to 

 express emotional variations by aid of their humming sound. " A 

 tired bee,' ; says Sir John Lubbock, "hums on E', and therefore 

 vibrates its wings only 330 times in a second." A bee humming on 

 A' will, on the other hand, increase its vibrations to 440 per second. 

 " This difference," says Sir John, " is probably involuntary, but the 

 change of tone is evidently under the command of the will, and thus 

 offers another point of similarity to a true ' voice.' A bee in pursuit 



