THE SENSES OP INSECTS. 245 



close to earth again, and then, having regained the scent, came 

 sailing along." 



In approaching the question of hearing, it is interesting to 

 observe two great insect divisions — those which emit audible 

 sounds and those which do not. In the first division, the bee, 

 housefly, gnat, some of the beetles, cricket, and grasshopper may 

 be cited as examples ; in the second, butterflies, moths, dragon- 

 flies, ants, and many dipterous insects. I am aware that ob- 

 jection may be made to this classification, but it is the result of 

 close observation. In the prevailing desire to show that all 

 classes of insects produce audible sounds, I feel bound to say that 

 science in making the claim for, say, dragonflies and the pea- 

 cock butterfly {Vanessa io), appears driven to extremity. And 

 my observation compels me to doubt if the hum of the bee, as an 

 example of humming insects, is to be at all attributed to wing- 

 vibration. Eather is it, I believe, to the possession of musical 

 spiracles used in flight for the inflation of the body. Nature has 

 landscape sounds for our ears, just as she provides scents for 

 smell or colours for the eye. What though all insect sounds are 

 not agreeable — neither are all flower scents, or flower colours ! 

 For monotony is not conducive to human pleasure, but contrast 

 is ! Enough, however, has been said to show that some insects 

 produce audible sounds, and I have dilated upon the point because 

 it has been suggested that such insects can necessarily hear. On 

 the other hand, it is obvious that the mere ability to produce 

 sound is no proof that a creature can hear at all. 



Stories, nevertheless, are related of scientific observations 

 pointing to the conclusion that some, at any rate, of the insects 

 named can not only hear, but interpret the sounds they produce. 

 If in the study of these narratives there arises a suspicion that 

 science can end and enthusiasm begin, there is certainly a general 

 testimony in favour of the possession of auditory powers which 

 has all the weight of highest authority. Thus we hear of the 

 queen bee using her vocal chords in an address to her subjects, 

 the beetle finding his mate by her stridulation, the female cricket 

 the male by his chirruping, &c. 



Eeferences such as these would be incomplete if the scientist 

 could not point to auditory "organs" in sound-producing insects. 

 Instead of loading the antennse with sole responsibility, these 

 structures are now considered to divide the function with others 

 distributed over various parts of the body. Thus we are told of 

 the " halteres" at the wing-bases of flies, the tympanum on the 

 first abdominal segment of true locusts, and the ears carried by 

 crickets on their legs. Touch, we know, is distributed over the 

 whole of an insect's body. Whether these microscopic "organs" 

 are in conjunction with touch, or hearing, may for the present be 

 dismissed to the specialist and the lens of the future. Neither 

 can I afford more than a passing reference to what is inferred 



