264 INSECT ARTIZANS AND THEIR WORK 



When the insect rapidly moves its wings the file 

 of the one lobe is scraped sharply across the horny 

 margin of the other, thus producing the sounds ; 

 the parchmenty wing-cases and the hollow drum- 

 like space which they enclose assisting to give 

 resonance to the tones. 



" The projecting portions of both wing-cases 

 are traversed by a similar strong nervure, but this 

 is scored like a file only in one of them, in the other 

 remaining perfectly smooth. Other species of the 

 family to which the Tanana belongs have similar 

 stridulating organs, but in none are these so highly 

 developed as in this insect ; they exist always 

 in the males only, the other sex having the edges 

 of the wing-cases quite straight and simple." 



He proceeds to give a brief description of the 

 variations in this apparatus in the other families, 

 which is so terse that it is worth quoting further : 



" In the common Field Cricket of Europe the 

 male has been observed to place itself, in the even- 

 ing, at the entrance of its burrow, and stridulate 

 until a female approaches, when the louder notes are 

 succeeded by a more subdued tone, whilst the suc- 

 cessful musician caresses with his antennae the mate 

 he has won. Any one, who will take the trouble, 

 may observe a similar proceeding in the common 

 House Cricket. 



" The nature and object of this insect music 

 are more uniform than the structure and situation 

 of the instrument by which it is produced. This 

 differs in each of the three allied families above 



