174 On the Sound Organs of the Green Cicada. 



produce their music. For many years Reaumur's explana- 

 tion of the process, published in 1740, in his Memoires*, 

 was generally received; but in 1872 Landois published a 

 monograph on '^Die Ton-und Stimm-Apparate der Insekten" 

 in the Zeitschrift fur Wissenschafiliche Zoologie, in which 

 he advanced a novel theory on the subject. I have not been 

 able to obtain access to the original paper, but Huxleyf* 

 quotes Landois as contending that " the posterior thoracic 

 stigmata are the vocal organs. These open into chambers^ 

 in the walls of which tense membranes are so disposed as 

 to intensify the sound by their resonance." In this view 

 clearly, then, the sound is a true voice, produced as in man 

 by a modification of the tubes of the breathing apparatus. 



This is a taking theory. Nor is it so easy for European 

 naturalists, save on their travels, to verify or discredit it for 

 themselves. Thus there is but one tiny British species, and 

 that now only rarely to be found in the New Forest. The 

 European forms cannot compare in size with some of our 

 own, and with many exotic species. The life of the adult 

 insect is a short one, and exotic specimens could not be 

 taken to England to repeat their performances before a 

 scientific jury. From the habits of the larvse, the rearing of 

 cicadas would be attended with great difiiculty. Reaumur 

 himself writes J: — 



'^ Heureusement que ces parties, les plus singulieres de 

 I'ext^rieur de ces mouches, peuvent etre bien vues sur celles 

 qui sont mortes; et que pour les etudier et les dissequer a 

 I'aise il faudroit faire perir les cigales qu'on auroit vivantes; 

 car je me suis trouve engage a 1 ecrire leur histoire sans en 

 avoir jamais entendu chanter une, et sans en avoir jamais 

 possede une en vie." 



Anatomy certainly gave Reaumur the clue to the correct 

 theory, but we need also to bring the rival theories to crucial 

 tests by experiment in order to definitively determine 

 between them. 



I was much exercised, as. every new comer must be, on 

 listening to this noisy Victorian species for the first time in 

 1883. By dissection and a few simple experiments I made 

 out what I conceived to be the modus operandi, and all 

 my observations agree with the older theory of Reaumur, 



* Tome 5. 



f Anatomy Invertebrated Animals, page 438. 

 -I Memoires, tome 5, page 149. 



