Zöology; a textbook for colleges and universities . From Brehms ThierlebenFIG. in. A group of cockroaches, showing individuals in various stages of growth. GRASSHOPPERS AND THEIR RELATIVES 315. From Bulletin 67, U. S. National Museum and experts can often distinguish between closely re-lated forms by their voices. It is also found that thesound proceeds fromquite different parts ofthe body in differentkinds; it may be thelegs, the tegmina, or theabdomen. In no case,of course, does it comefrom the mouth, as withus. Various studentshave tried to record OrthopterOUS SOngS in FIG. 112. A tree cric
Zöology; a textbook for colleges and universities . From Brehms ThierlebenFIG. in. A group of cockroaches, showing individuals in various stages of growth. GRASSHOPPERS AND THEIR RELATIVES 315. From Bulletin 67, U. S. National Museum and experts can often distinguish between closely re-lated forms by their voices. It is also found that thesound proceeds fromquite different parts ofthe body in differentkinds; it may be thelegs, the tegmina, or theabdomen. In no case,of course, does it comefrom the mouth, as withus. Various studentshave tried to record OrthopterOUS SOngS in FIG. 112. A tree cricket (Orocharis): a, fe-1 • j male; b, male. musical notation, and in so doing have brought out some interesting some cases we find simply the monotonous repe-tition of a single note; but in others there is a regularvariation, the sound rising and falling to produce truerhythm. Sometimes the song is in such a high keythat it is inaudible to some human ears, though seem-ing loud to others. 3. As might be expected in such a primitive group, Mouth partsthe mouth parts are adapted for biting, not for suck-ing; and the metamorphosis is incomplete. Bythe latter expression we mean
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectzoology, bookyear1920
