174 N. E. McINDOO 



In regard to the buzzing of insects, there are four old views to 

 explain how the noise is made, as follows: 1) by the rapid vibra- 

 tion of the wings; 2) by the vibration of the thorax; 3) by a special 

 modification of the occlusor • apparatus in the stigmata, • and, 

 4) in Diptera, by the vibration of the halteres. Relative to 

 Diptera, and Hymenoptera, Pemberton ('11) and Aubin ('14) 

 show that none of the above views hold good. They determined 

 that the buzzing is made by the extreme bases of the wings, as 

 is shqwn for the honey-bee in the present paper. The humming, 

 or more common noise produced by the wings, is made by the 

 distal portions of the wings. 



We should not expect insects to respond to sounds which have 

 no significance to them, nor to sounds not in their category, 

 because they may not hear the sounds that we do. The number 

 of vibrations perceptible to the average human ear varies from 

 32 to 60,000 per second. Now it may be that the insect ear is 

 so poorly developed that it can hear only sounds having vibra- 

 tions below 32 per second. It may also be that the sense of 

 hearing in insects is on no higher plane than that advocated by 

 Forel C08), who believes that insects do not hear, at least as we 

 do, but compares this perception in them to that in deaf-mutes 

 who feel the rolling of a carriage at a distance. 



Bee-keepers are agreed that bees can hear, yet they cannot 

 prove it. Von Buttel-Reepen ('07), a scientist and an ex- 

 perienced bee-keeper, in discussing the behavior of bees has much 

 to say about their auditory perception, but still he produces no 

 experimental evidence to support his strong statements. 



To obtain material for the structure of the sound-producing 

 organ, adult bees were used; but for a study of the so-called 

 auditory organs, young bees, nineteen and twenty-one days old 

 (counting from the time the eggs were laid) were employed. 

 Fresh material was fixed in the modified Camoy's fluid and was 

 embeded in 60° paraffin. Sections were cut 5 and 8 m in thick- 

 ness, and were usually stained in Ehrlich's hematoxyhn and eosin 

 but a few of them in eosin alone. All the drawings are original 

 and were made by the writer at the base of the microscope usually 

 with the aid of a camera lucida. 



