234 ANIMAL LIFE 
has on the upper surface of the first abdominal segment 
a pair of tympana or ear-drums (Fig. 147), composed sim- 
ply of the thinned, tightly stretched chitinous 
cuticle of the body. On the inner surface of this 
Fie. 147.—Grasshopper, showing auditory organ (qa. 9.) in first segment of abdomen. 
(Wings of one side removed.) 
ear-drum there are a tiny auditory sac, a fine nerve lead- 
ing from it to a small auditory ganglion lying near the 
tympanum, and a large nerve leading from this ganglion 
to one of the larger ganglia situated on the floor of the 
Fia, 148,—A cricket, showing anditory organ (a. 0.) in fore-leg. 
thorax. In the crickets and katydids, insects related to 
the locusts, the auditory organs or ears are situated in the 
fore-legs (Fig. 148). 
Certain other insects, as the mosquitoes and other midges 
