124 Generation of Sounds by Canadian Insects. 



the abdomen and hind legs, these form a large exterior moveable 

 cartilaginous curtain or membrane, which, when raised, exposes 

 a cavity, part of which seems to extend into the abdomen, and 

 part to be covered with a second thin and pellucid membrane, 

 much more delicate than the exterior one, and tensely stretched, 

 plicated, and iridescent. In the middle there is a horny plate 

 running horizontally across the bottom. It is this iridescent 

 membrane which is acted -«pon internally by a bundle of muscular 

 strings which throw it into rapid vibration, and thus gives rise to 

 the sound. These minuie muscular strings are attached by one 

 extremity to another membrane in the interior, which is presumed 

 to be the true drum, from the fact, that when Reaumur*, who is 

 describing the mechanism of the sound produced, compares it to 

 that issuing through an opening like that of the larynx of qua- 

 drupeds, or the sound-hole of a violin. 



This most curious apparatus has attracted the attention of many 

 of the most celebrated physiologists, and a desire is manifested on 

 the part of some of them to know whether any actual difference 

 exists in its construction in Cicadce, existing in other parts of the 

 world besides Europe. As Greece and Italy are the two countries 

 in which it abounds, the familiarity with its history evinced by 

 Anacreon, Aristotle, Pliny, Virgil, and some other ancient authors 

 is fully explained. There can be no doubt that Aristotle refers to 

 the Cicada, when he speaks of the voices of insects, especially of 

 " a shrill, long-drawn note, like the grass-hopper." Pliny speaks 

 of the Cicada, but there is no doubt that he, as well as Aristotle has 

 confounded grass and tree-hoppers together. 



Whether the sound is pleasing to the ear is a question ; assur- 

 edly when it proceeds from a number, its shrillness and frequent 

 repetition becomes fatiguing. I cannot say that it was displeasing 

 to myself, perhaps because my curiosity was amply repaid by its 

 capture and examination of the insect, and because I won- 

 dered, in common with others, that such a shrill and loud 

 sound should proceed from such a small creature : its music 

 being more audible than that of many birds. In the forests 

 of South America at certain periods of the day nothing is 

 heard but a loud and uninterrupted rustling or humming 

 noise, produced by various insects, in which the notes of the 

 Cicada3 predominate. Kirby and Spence mention on the autho- 



* See Cuvier's Animal Kingdom 1849, page 569 for a more minute and 

 strictly anatomical account. 



