ON THE FUNCTIONS OF THE ANTENNA. 591 



and names of the first rank come before us in the investigation 

 of the history of this controversy ; no subject, perhaps, in 

 zoology has been treated with greater acumen, and yet to-day 

 (1883), in spite of the many essays of the last ten years, we are 

 far from a final solution of the questions involved.' 



Krapelin gives references to more than one hundred papers 

 on the subject, ranging from 1730 to 1883. 



Lubbock [276], in 1888, said : ' The evidence is, I think, 

 conclusive that the antennae are olfactory as well as tactile 

 organs, and I believe that they also serve as organs of 

 hearing.' 



Observations in Favour of an Auditory Function. Kirby (' Intro- 

 duction to Entomology ') observed movements of the antennae 

 in a Moth and in a Weevil when he made a distinct sound in 

 their vicinity, and other observers have asserted that the 

 antennae are set into vibration by sounds. Mayer went a step 

 further, experimenting with the feathered antennas of a male 

 mosquito (Culex), he found that some of the hairs are thrown 

 into vigorous vibration, when a note with 512 vibrations per 

 second is sounded. Lubbock [276], who quotes the observa- 

 tion, adds : ' It is interesting to observe that the hum of the 

 female Gnat corresponds nearly to this note, and would, conse- 

 quently, set the hairs into vibration.' To my ear, however, the 

 note of the female Gnat is certainly not middle C, which has 

 512 vibrations, but A, as is usually stated with 420 double 

 vibrations. 



It may be remarked that the vibration of the setae in response 

 to certain notes is a physical necessity, but it is not evidence 

 that they are endowed with auditory sensibility ; neither is the 

 voluntary movement of the antennae when an insect is excited 

 by sound better evidence. A terrier will certainly sniff when 

 he hears a rat, but this is not evidence that he hears with his 

 nose; the dog is simply using his most acute sense to determine 

 the cause of a sound. And so insects may use their antennae 

 when excited by sounds, even if they do not hear with them. 

 Lehmann [261] believed that insects hear with their antennae, 

 and he found that those of a Cricket (Acheta domestica) vibrate 



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