234 TRUE TALES OF THE INSECTS. 



ascribed to the forcible expiration of air through the tongue 

 or trunk ; and it is said that bubbles have been seen to 

 form upon the tongue when the moth had been induced 

 to squeak under water. A large dome- shaped cavity has 

 been shown to exist in the head, which, by the alternate 

 action of elevating and depressing muscles, is caused to 

 act as a bellows, and probably inhales, as well as exhales, 

 air through a narrow slit-like aperture, leading to the 

 proboscis. That the air expelled enters the cavity from 

 behind, as has been supposed, is hardly likely, for the 

 posterior opening is small, if not often altogether aborted, 

 while the animal can still squeak if its abdomen be 

 removed. At the narrow slit-like opening the note is 

 formed, the sound being modified by passage through 

 the proboscis tube. 



But it has been satisfactorily proved that the pupa 

 has the power of squeaking like the moth shortly before 

 emergence, and, it must be confessed, it is difficult to 

 understand how the methods of production suggested 

 can operate in this case. Strange to say, the larva has 

 also a voice, of a totally different nature however, being 

 a peculiar grating or crackling noise, that may be com- 

 pared to the snap that accompanies an electric spark, 

 and sometimes the noise is repeated in rapid succession, 

 resembling that occasioned by the winding up of a watch. 

 Cottagers finding the caterpillar have described it, not 

 inaptly, as biting its teeth at them. There is no doubt 



