THE ORTHOPTERA 87 



pers," "Jerusalem crickets," etc., according to tiieir kind and the local 

 usage. 



Sound in this family is produced by the males. The base of the 

 fore wing is modified, not necessarily in the same way in all the species, 

 but in such a manner that rubbing these wings together will produce a 

 sound. The organ of hearing is a small, oval membrane located near 



Fig. 67. — " Wingless Grasshoppor," natural size. (Original.) 



the base of the tibia on each side of the front leg. Inside the membrane 

 is a hollow space or resonance chamber, and a nerve supply. The sounds 

 made by these insects are produced chiefly toward evening and at night, 

 though in dense woods they may sometimes be heard earlier in the day. 

 The members of this group are rarely serious pests, though katydids 

 have been knoM^n to injure orange groves and presumably some forest 



Fig. 08. — "Western Cricket" {Anabrus purpurascens Uhl.), slightly enlarged. {After 



Gillette.) 



trees suffer more than is generally realized, when these insects are abun- 

 dant. One exception to this general unimportance of the family is met 

 with in the case of the wingless species known as the "western cricket" 

 {Anabrus purpurascens Uhl., Fig. 68), which in some of the Western 

 States may be a serious crop pest. 



