92 EVENINGS AT THE MICROSCOPE. 



weaker vibrations of the contracting muscles, and con- 

 sequently less forcible expulsion of the air when the 

 vibratory organs are removed ; and he thinks, with 

 Chabrier, that some air may escape through the open 

 trachece of the wings which are cut off. Though he 

 regards these lamina? as the cause of humming in bees 

 and flies, he does not decide that other causes may not 

 produce the buzz of cockchafers, etc., in the thoracic 

 spiracles of which he could not discern them.* 



* a 



Man. of Entom.,"46S. 



