14 NATURAL HISTORY SOCIETY OF DUBLIN. 



dumb. Its mechanism is not yet explained ; a committee of French Lepi- 

 dopterists ("An. de la Soc. Entom. de France," 1839), discussed and 

 examined the explanations offered of it, and suggested some themselves, 

 but the mystery has not yet been solved. The theories advanced to 

 account for the noise are enumerated and combated in Westwood and 

 Humphrey's " British Moths" (vol. i., p. 10, 1843). 



A writer in the " Ent. Monthly Mag.,'' vol. v., p. 171, speaking of a 

 death's head moth captured October, 1868, says it frequently emitted the 

 sounds peculiar to its species, always raising the thorax, and bending 

 down the head and abdomen as it did so. When breathing its last, it gave 

 out a long succession of sounds, growing fainter and fainter, just like a 

 succession of breathings, giving him the impression that the noise was 

 produced, not mechanically by friction, but by inspiration or respira- 

 tion of air. It made the noise when he first had it, every time he merely 

 touched it with his finger; but when it got accustomed to such treat- 

 ment, it never made it without rather rougher handling. 



The sounds made by the death's head moth are strong or weak, ac- 

 cording to the amount of vitality in the insect at the time; thus the 

 cries of one caught two days, and which had been pierced with a pin, 

 were noticed to be weak and faint, and seldom uttered. The sound is 

 not made by voice, in the true sense of the word, but rather by some 

 sound-producing instrument ; so that sonorous insects are not songsters, 

 but rather instrumental musicians. The buzzing of insects is not in- 

 cluded in the term sonorous. The emission of sounds in insects is very 

 interesting, a§ nearly all the class are mute. The subject has been very 

 fully treated by M. Goureau in " An Essay on the Stridulation of In- 

 sects" ("Entomological Magazine," 1838, vol. v., pp. 89, 357). 



The death's head moth is not the only lepidopterous insect capable 

 of making a noise. It has been long known that one of the tiger moths 

 (Chelonia pudica) found in France, produces an audible sound when fly- 

 ing in the evening. Dr. Laboulbene, an entomological anatomist of great 

 repute, has investigated the cause of this sound, and has arrived at the 

 conclusion that it is caused by the pressure of the posterior thighs upon 

 certain tympaniform vesicles on each side of the pro-thorax. Sounds are 

 also produced in the species of the genus Setina, which possess a highly 

 developed vesicle, and the cause of the sound is considered to be the 

 same as in Chelonia pudica (" Ent. Monthly Mag.," vol. ii., p. 70). 

 Basiana postica (Port Natal) gives out sounds resembling those of a 

 Lamia (a beetle of the longicorn family) for minutes together — (" Brit. 

 Mus. Cat. of Lepidop., Heterocera," pt. 8, p. 237). All the species of 

 the genus Ageronia (a genus peculiar to the tropical parts of America), 

 whose history is known, produce in flying a sound which a good 

 observer has compared to the rustling of apiece of parchment, to which, 

 also, M. Lacordaire compares it. Mr. Darwin, in his "Researches in 

 Geology and Natural History," has the following passage in regard to 

 one species of this genus, Papilio feronia: — "A far more singular 

 fact" — the fact alluded to is, that this butterfly uses its legs for running, 



