OETHOPTEEA. 293 



object to call the females, is nothing but a sort of stridulation or 

 screeching, produced by the rubbing together of the wing cases or 

 elytra. But the mechanism by which this is produced varies a 

 little in all the three kinds. With the Crickets the whole surface 

 of the wing cases is covered with thick nervures, very prominent 

 and very hard, which cause the noise the insect produces in rub- 

 bing the elytra one against the other. With the Locusts, there 

 exists only at the base of the elytra a transparent membrane called 

 the mirror, which is furnished with prominent nervures, and 

 produces the screeching noise. And, lastly, in the Crickets the 

 thighs and elytra are provided with very hard ridges. The 

 thighs, being passed rapidly and with force over the nervures of 

 the elytra, produce the sound, in the same way as a fiddle-bow when 

 drawn across the strings of a violin. With all these insects 

 the male alone is endowed with the faculty of producing sound. 



The Crickets and Grasshoppers have very long thin antenna?, 

 whilst the Locusts have short antennae, and either flattened 

 or filiform, or swelling out at one extremity like a club. The 

 female of the first two is provided with an ovipositor in the shape of 

 an auger. 



We will study successively the three types of these families, 

 that is to say, the Crickets, the Locusts, and the Grasshoppers. 



Fip. 304. Field Cricket (Gryllus campestiis). 



The Field Cricket ( Gryllus campestris, Fig. 304) lives alone in a 

 hole which it digs in the ground, and in which it remains during 

 the day. It only quits its retreat at night, when it goes in 



