90 BUTTERFLY SOUNDS 



time a loud and most singular snapping or crack- 

 ling noise, wliicli I can best compare to the sound 

 of a slight electric spark, at intervals of one to 

 five seconds. This sound is particularly distinct 

 when the male is chasing the female, and I have 

 heard it at a distance of at least ten yards. I 

 think it is produced by both sexes." Wallace 

 observed the same thing at Para, and believed 

 that it was produced in some way by the contact 

 of two insects, as he only heard it when two 

 insects were chasing or frolicking with each other, 

 and it seems to be the general belief that the 

 sound is common to both sexes, which Mr. Van 

 Volxem positively asserts. 



But, as stated above, these sounds are emitted 

 also by butterflies of the temperate regions. 

 Thus Mr. Swinton, who has written a good deal 

 upon this subject, states that the Small Tortoise- 

 shell (Agiais urticae), about to hibernate and 

 in a drowsy condition, was induced by him to 

 depress and shut the wings successively, and 

 " each time she testily performed this action I 

 heard distinctly, as the fore wings were brought 

 forward, when only the extreme basal portion of 

 the wings was in contact, a sound soft and refresh- 

 ing, like evening footsteps on the pavement, or 



