592 THE SENSES AND SENSORY ORGANS. 



to certain notes, yet he admits that this insect undoubtedly 

 hears when the antennae are removed. 



Neither is the anatomical and histological evidence more 

 satisfactory. Leydig, Graber, and Hurst have described struc- 

 tures which they believed to be auditory. Leydig's chordo- 

 tonal organs in the antennas of Dytiscus are very doubtful. 

 Graber describes similar organs in the antennae, palpi, under lip 

 and legs of Dytiscus and Telephorus without figuring them. 

 Hurst [156] describes and figures a structure in the basal joint 

 of the antenna of Culex, and Hammond has shown me some 

 very beautiful sections of this organ. Both observers regard it as 

 an ear ; but, I think, on very insufficient evidence. The scape 

 of the antenna is supported by a thin membrane, beneath 

 which there are, undoubtedly, very remarkable nerve ter- 

 minals. 



This organ is certainly an exceptional one, and it may be 

 admitted that the presence of an ear at the base of the anten- 

 nule in some Crustacea is an argument in favour of the view of 

 Hurst and Hammond. It appears to me more probable, how- 

 ever, that the pressure communicated to the tense membrane 

 by the action of the air on the great plumose antenna during 

 flight would affect this membrane more powerfully than sound 

 vibrations, and I think it more probably a balancing organ than 

 an auditory organ in the strict sense of the word. I do not 

 wish, however, to deny the existence of auditory organs in con- 

 nection with the antenna, although I feel that the evidence in 

 favour of such organs is far from convincing. The structure in the 

 second joint of the antenna of the Blow-fly certainly resembles 

 a rudimentary group of chordotonal organs, and perhaps 

 indicates the existence of auditory organs in the antenna. I 

 have not been able, however, actually to make out chordotonal 

 threads, and it appears to me improbable that the antennae are 

 organs of audition in insects. 



Experimental Evidence in Favour of an Olfactory Function. Ferris 

 [265] gives numerous experiments which led him to the conclu- 

 sion that the antennae are olfactory organs, and Hauser [272] 

 arrived at the same result. The latter says that neither Silpha 



