AUDITORY POWERS OF CATOCALA MOTHS. 2/9 



esting to observe that an auditory sense is certainly present in 

 these insects. Several kinds of moths have the habit of gently, 

 though very rapidly, vibrating their wings, while they them- 

 selves are at rest on a flower or other surface. If, while this 

 vibrating movement of the wings is going on, the observer makes 

 a sudden shrill note with a violin, or fife, etc., the vibrating 

 movement immediately ceases, and sometimes the whole body 

 of the insect gives a sudden start. These marked indications of 

 hearing I found invariably to follow a note with a high pitch, 

 but not a note with a low one." 



Heinrich ('09) remarks that collectors using a net to capture 

 Limenitis populi and Catocala fraxini have observed that the 

 insects often take flight before a collector is near enough to cap- 

 ture them. Accordingly to him no conclusive evidence has been 

 published on the sense of hearing of insects, especially of the 

 Lepidoptera. He noticed a Laurentia suffumata alight in a con- 

 cert pavilion and remain quietly while the brass band played 

 three selections, one of which was Wagner's Gotterdammerung. 

 He also noticed that certain Lepidoptera were more easily 

 approached at twilight than when the sun was shining brightly, 

 and he could not understand why this should be true if they were 

 warned by a sense of hearing. He is convinced that, in all of 

 these cases, it is vision, not audition, that warns butterflies 

 and moths of the approach of man. 



Hamann ('09) was led to investigate this subject by the 

 remarks of collectors that butterflies and moths undoubtedly 

 hear. One collector remarked that the noise caused by removing 

 the cork from the cyanide bottle often caused these insects to fly. 

 To this Haman replies that since the net is usually placed beneath 

 the insect before the cork is removed it is probable that the sight 

 of the net caused the flight. To test the matter, the following 

 experiments were performed by him. (i) He approached a tree 

 in such a manner as to be invisible to an Apatura iris L. resting 

 thereon, and struck the tree with the bamboo handle of his 



several species of Lepidoptera that emit sounds. Indeed, scarcely had his article 

 appeared before several of his contemporaries published, in Nature, protests in 

 which were cited several examples of sound-producing Lepidoptera. Recently 

 Omensetter ('12) and Stephan ('12) have described several sound-producing forms 

 of butterflies and moths. 



