98 INSECT MISCELLANIES. 



these scales by the action of the wings. M. Lorrey 

 again states that the sound arises from the air escap- 

 ing rapidly through peculiar cavities communicating 

 with the spiracles, and furnished with a fine tuft of 

 hairs on the sides of the abdomen.* M. Passerini, 

 curator of the Museum of Natural History at Flor- 

 ence, has lately investigated the subject more minute- 

 ly. He traced the origin of the sound to the interior 

 of the head, in which he discovered a cavity at the 

 passage where muscles are placed for impelling and 

 expelling the air. M. Dumeril has since discovered 

 a sort of membrane stretched over this cavity like, as 

 he says, to the head of a drum. M. Duponchell 

 has also confirmed by experiment the opinions of Pas- 

 serini and Dumeril, and confutes Lorrey, by stating 

 that the noise is produced from the head when the 

 body of the insect is removed. | 



The death's-head moth is not the only insect whose 

 sound alarms the superstitious. Insects, which are 

 much more common, though from their minuteness 

 not so often seen as heard, often strike the unedu- 

 cated with terror as the messengers of death. We 

 refer to the sound which most of our readers may 

 have heard issuing from old timber or old books, re- 

 sembhng the ticking of a watch, and hence popu- 

 larly called the death-watch. Some writers, who 

 are desirous of being thought very accurate, are 

 particular in distinguishing a certain insect as the 

 genuine death-watch, while others are held to be 

 spurious ; yet there can be no doubt that the same 

 sort of ticking is produced by several species. La- 

 treille, indeed, seems to say that it is common to a 

 whole genus {Jhwhium, Fabr. J) ; and besides these, 



* Stephen's Illustr. (Haust.) i, 116. 

 t Annales des Sciences Naturelles, Mars., 182§^ 

 X Families Naturelles, i, 484, ed. 1829, 



