GRASSHOPPERS AND THEIR RE L AT I FES 



315 



and experts can often distinguish between closely re- 

 lated forms by their voices. It is also found that the 

 sound proceeds from 

 quite different parts of 

 the body in different 

 kinds ; it may be the 

 legs, the tegmina, or the 

 abdomen. In no case, 

 of course, does it come 

 from the mouth, as with 

 us. Various students 



have tried tO record From Bulletin 67, U.-S. National Museum 



OrthopterOUS SOngS in FIG. 112. A tree cricket (Orocharis) : a, fe- 

 i , j male: b, male. 



musical notation, and 



in so doing have brought out some interesting features. 

 In some cases we find simply the monotonous repe- 

 tition of a single note ; but in others there is a regular 

 variation, the sound rising and falling to produce true 

 rhythm. Sometimes the song is in such a high key 

 that it is inaudible to some human ears, though seem- 

 ing loud to others. 



3. As might be expected in such a primitive group, Mouth parts 

 the mouth parts are adapted for biting, not for suck- 

 ing; and the metamorphosis is "incomplete." By 

 the latter expression we mean that the infant grass- 

 hopper, on hatching from the egg, is visibly a grass- 

 hopper not a grub, maggot, or wormlike animal. 

 It is remarkable as is the case with human infants 

 for the relatively large size of its head, and it has no 

 wings. At this early period of its life it can hop well, 

 but it is entirely mute. The grasshoppers' children 

 literally obey the injunction that they should be seen 

 but not heard. In many cases they avoid even being 

 seen, owing to their close resemblance to inanimate 



