316 TENA^^TS OF AN OLD FARM. 



larg(! valvfs beneath the bell}^ and which are separated 

 from each other by thin partitions having the trans- 

 parency and briUiancy of thin and highly polished 

 glass. In most of our species of Cicada the drums are 

 not visible on the outside of the body, but are covered 

 by convex triangular pieces on each side of the first 

 ring behind the thorax, wliich must be cut away in 

 order to expose them. Now, if we raise the large 

 valves, of which I spoke, there is seen close to each side 

 of the body the little opening like a pocket in which 

 the drum is lodged, and from which the sound issues 

 when the insect opens tlie valve." 



" Sir," said Harry, "you have shown us the drum- 

 head and the drum-barrel, but where are the drum- 

 sticks ?" 



'' You forget ; I liave already spoken of them. They 

 are the muscles or cords fastened to the inside of the 

 drums, by which the heads are made to rapidly tighten 

 and loosen. Unfortunately, I cannot show you these 

 without better optical aids than we have here ; but you 

 must take their existence on faith or anthorit}', as one 

 has to do very many things in Natural History. The 

 eOect of the rapid alternate tension a!ul relaxation of 

 these drum-stick muscles and the membrane attached 

 to them, is the production of th(^ rattling buz/, which 

 constitutes the familiar music of the cicada. And now 

 that I have given my illustration, I shall ask Harry to 

 give one which he has prepared at my request." 



Harry blushed and hesitated, but fiually took from 

 liis pocket an iustrument with wliieh my own boyhood 



