EXTERNAL ANATOMY. 



61 



shorter and carries but one pad. The third is long and 

 slender, with two curved, pointed claws or ungues {iin), be- 

 tween which is a concave sucking disk, the fourth joint or 

 pulviUus {pv)- The first and second pairs of legs are much 

 like the third, but much smaller, and they meet the body at 

 a different angle, to fit them for crawling instead of leaping. 

 The Abdomen. — This is made up of a number of seg- 

 ments without appendages, movable upon each other, and 

 presenting only slight differences. The typical number of 

 abdominal segments appears to be eleven, and in both sexes 

 eleven terga are present, although only eight sterna are vis- 

 ible in the female and nine in the male. Fig. 36 shows a cross- 

 section through the abdomen of a locust. The first abdominal 

 segment is somewhat different from the others 

 and its sternal and tergal portions are vv^idely 

 separate. The sternal portion is immovably 

 united to that of the metathorax, and has been 

 already described (afot/. st)(Fig.30). Thetergum 

 is soft, membranous, and dark-colored like those 

 of the thorax, and is strongly crested in the med- 



section through • i* tvt 'j. 1 J • r i 



abdomen. lau Imc. Near its lowcr cdgcs are a pair ot large 



apertures closed by membrane, the auditory- 

 organs, (Fig. 37, au), or ears. On the anterior margin of 



this orifice is a much smaller 

 opening, the first abdominal 

 spiracle, (Fig. 37, sp). The 

 remaining abdominal seg- 

 ments are composed of a 

 narrow sternal portion and 

 a much larger tergal one. 

 The two sides of thetergum 

 meet along the back to form 

 a ridge. Near the lower 

 margin of each half of the 

 tergum is a couple of longitudinal furrows, the traces of 

 the sutures between theepimera and the cpisterna. Near the 



Fig. 36-Cross- 



FIO. 37. — Auditory organs {au) of Mel 

 finoplus bivittattis' (A), and of a Katy- 

 did (B). Original. 



