INSECT HEARING. 3/5 



A little later its hind legs were cut off, and the wound closed 

 with gum. "When replaced on the table it sprang suddenly aside 

 on letting a pencil fall, which noise did not in the least affect the 

 insect before. It also leaped up when a scratching noise was 

 made, the le^ps being violent in proportion to the loudness of the 

 noise. The insect's nerve sensitiveness was obviously increased by 

 mutilation. 



3. A few hours afterwards the same insect being placed on a 

 thick piece of cork still leaped up when a piercing rasp sound was 

 produced, but a little later no noise whatever could make it move, 

 its hearing faculty being gradually exhausted by the constantly 

 repeated sounds. 



4. The two antennae were next cut off, and immediately after, 

 on taking up the knife off the table, which act was accompanied 

 by a slight rustling sound, the insect suddenly shook itself 

 together. Later on it responded to the sound made by striking 

 the knife blade against a ruler by crawling forwards with struggling 

 movements of its legs, but remaining at intervals motionless. 



5. After some hours the mutilated insect was again operated 

 upon, the so-called spoon-shaped organs being extirpated, and 

 being left for some hours it sprang up from the cork on which 

 it lay when the noise was again made. 



6. The next day the insect could not re-act when the most 

 piercing shrill tone was made, but was extremely restless when 

 the table on which it lay was struck, and finally it shuddered 

 whenever the table was struck with the finger, which a perfectly 

 fresh unmutilated insect does not do. 



7. The front pair of legs (containing the auditory organs) was 

 cut off from a fresh insect, and the wound closed with gum. It 

 rested unmoved on the table. As often as a noise was made by 

 striking two rules together the hind legs began to tremble, but the 

 trembling ceased when the noise ceased. When the insect was 

 placed on its back it remained quiet, but the trembling began again 

 as boon as the noise was repeated. 



