326 ZOOLOGY. 
sound, heard and appreciated by individuals of the otiner 
sex. Any insect which produces a sound must be supposed to 
have ears to hear the sound pro- 
¢ duced by others of its species. 
i! In the antenne, palpi, and 
abdominal appendages of dif- 
‘ferent insects are seated mi- 
; nute olfactory organs consisting 
donthalappendeges ofa 9 Chr yeopia) of pits alone (Fig. 285), or of 
Sa per en he terminal joint ot hairs perforated at the end, and 
pegs associated with the pits. 
The ears (or auditory sacs) of the locust are situated, one 
on each side, on the basal joint of the abdomen, just be- 
Fig. 286.—Ear of a locust (Caloptenus italicus) seen from the inner side. 7’, tym- 
panum; 7'R, its border ; 0, u, two horn-like processes ; 5é. pear-shaped vesicle ; 7, 
auditory nerve ; ga, terminal ganglion; s¢, stigma ; 7, opening and m/ closing mus- 
cle of the eame; Jf, tensor muscle of the tympanum-membrane.—After Graber. 
hind the first abdominal spiracle (Fig. 274). The ap- 
paratus consists of a tense membrane, the tympanum, sur. 
rounded by ahorny ring (Fig. 286). ‘* On the internal sur- 
