BUTTERFLY SOUNDS 99 



human perceptibility of sounds from their shrill- 

 ness and also from their feebleness. It is known, 

 but perhaps not well known, that there are a cer- 

 tain number of saltatorial Orthoptera which can 

 be seen to stridulate but whose sounds are inaudi- 

 ble to our ears. From the fact that certain but- 

 terflies produce sound during certain movements, 

 we can hardly fail to believe that other butterflies 

 making the same motion also produce sound, al- 

 thoug-h inaudible to our ears. 



Nor are the sounds made by these friends of 

 ours altogether limited to the butterfly state, a 

 large number of caterpillars making sounds by 

 striking their heads against the leaf upon which 

 they are resting, or by swinging the head from 

 side to side, catching the mandibles in the rough- 

 nesses of the leaf or upon the silken strands which 

 they have spun upon it, to produce a scraping 

 sound to drive away intruders ; and Schild states 

 that the chrysalis of the Green Hair-streak (Callo- 

 phrys rubi) when disturbed produces by its move- 

 ments a slight sharp chirp, or, as Kleeman called 

 it in 1774, a clicking noise. But though I have 

 seen many chrysalids of Nymphalidae in exces- 

 sively active motion, I have never observed any 

 sound from this source. 



