OF INSECTS. 
131 
food ; - but when the part alluded to exists, the crop 
is furnished witli interior glandular organs which se- 
crete an active juice. These glands are most con- 
spicuous among the tiger-beetles, ( Cicindela ) even 
appearing in external rows on the obcordate shaped 
crop. (Plate II. fig. 2, b.) With very few excep- 
tions besides this, the surface of the crop is quite 
smooth. These remarks, however, apply to this 
part only as it appears among masticating insects ; 
in all other kinds, with the single exception of the 
Hemiptera, it becomes (or there is substituted in its 
place, according to the views we adopt regarding 
its origin,) what has not improperly been called a 
sucking -stomach. (Plate II. fig. 4, c .) Tts function is 
no longer to receive the alimentary substances trans- 
mitted from the mouth, but to facilitate the rise of 
the fluids from the mouth to the principal receptacles 
of the alimentary canal. This it promotes by dis- 
tending at the will of the insect, and thus rarifying the 
air in its interior and acting as a kind of pump. It 
presents various modifications of form in all the dif- 
ferent tribes possessing it. The crop is succeeded by 
the gizzard, (Plate II. fig. 2, c.) which may always be 
recognised, when present, by having its internal sur- 
face covered with teeth, spines, or horny ridges ; a 
structure which eminently fits it, in connection with 
its muscular, almost cartilaginous texture, for sub- 
jecting the food to a more complete trituration than 
it had previously undergone. It exists in all insects 
that feed on hard substances, such as wood, bark, 
&c., and in all carnivorous kinds ; but not in those 
