37^ INSECT HEARING. 



8. While perfectly quiet it happened that another grasshopper 

 kept in a cage at some distance begun to chirp, upon which the 

 hind legs of the insect experimented upon began again to vibrate 

 actively. 



9. Another insect whose hinder legs were cut off was laid on 

 its back. For a while it gesticulated with the other legs, then 

 became quiet. But at the first noise produced by striking the 

 knife-blade on the rule it drew up its body actively. 



10. Its head was then suddenly snipped off, and at the same 

 moment two rules were struck together. The legs remained 

 perfectly still, but the antennae and maxillary palpi moved. This 

 experiment was supposed to prove that the perception of sounds 

 was not affected by the tympanal organ of the front leg but 

 through the head. 



11. Some time afterwards on blowing upon the head (at 4" 

 distance) the maxillary palpi moved slightly and also moved when 

 tickled with a feather. On blowing tobacco smoke in the same 

 way over the head the palpi were withdrawn behind the back of 

 the head, (10 trials!) The same happened when the antennae 

 were cut oif so that this reflex movement of the palpi did not 

 depend upon antennal sensation. The effect of tobacco was 

 noticed four hours after decapitation, and on the following day 

 nineteen hours after. 



12. A cricket could not be got to respond to the screeching 

 sound of a glass stopper turned in the bottle in which it was 

 fitted. Its front legs were then cut off, but the insect remained 

 motionless, its other legs raised in the air. But on sounding the 

 E and A strings of a violin sharply at intervals of about four and 

 five minutes, the insect responded in a most ridiculously regular 

 manner by violent tetanic movements of its limbs though its 

 tympanal apparatus had been removed with the first pair of legs. 



13. The movements became irregular if the pauses were 

 shorter, but quite regular after longer intervals, when the same 

 tone had been frequently repeated, movements were excited more 

 readily excited by new tones. 



