SPECIAL SENSES OF INSECTS. 



17 



grasshopper is devouring its grass blade or the potato 

 beetle its wrinkly potato leaf. This may be watched 

 through a reading glass any day you find a leaf-eating 

 insect at its meals. 



Hearing. 



That the fifth of our senses is also possessed by many 

 insects is easier to believe than to prove. Anyone who 

 has ever listened to call and response of half a dozen'katy- 



FiG. 7. — Inner aspect of right tympanal sense organ of a grasshopper, 

 Caloptenus ilalicus. b, chitinous border; c, closing muscle of spiracle; gn, 

 ganglion; m, tympanum; n, nerve; 0, opening muscle of spiracle; p,p, processes 

 resting against tympanum; j, spiracle; tm, tensor muscle of tympanum; v, 

 vesicle. {Folsom, after Graher.) 



dids, or to two or three cicadas gossiping back and forth 

 on a July afternoon, with their musical "Ah- we — ah-we — 

 ah-we — ah-we-e-e-e-e-e !" does not lack proof in his own 

 mind that insects hear and make answer to what is heard. 



