CHAPTER IV 
THE SENSES OF INSECTS 
Ir is obvious that most-insects possess a well-developed power of 
sight. It is not believed that they have the ability to form images 
of objects, in other words to ~ 
(a3 
see,’ with the precision of higher ani- 
mals. Te a limited extent the compound eyes probably give an insect 
certain powers of forming images up to a short distance — not 
more than a few feet. They undoubtedly are well adapted to discern 
movement. The ocelli, or simple eyes, 
are formed somewhat on the plan of the 
human eye; but the lens is of fixed focus, 
and the number of nerves in the retina is 
comparatively small. 
The sense of hearing is well known to 
exist among many insects. The location 
of the auditory apparatus has been de- 
termined in certain species. Thus, the 
antenna of some insects are known to 
a 7 a ] y at] Ss * eTass rs, 
Ges cies ode aes have auditory functions; grasshoppers 
Enlarged and natural size. have an 
Original. 
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ear’ on the first segment. of 
the abdomen; other species have a 
similar organ on the foreleg. 
Most insects have a sense of taste. The hypopharynx, or tongue, 
and short appendages attached to the mavill:e, or lower jaws, are 
commonly the seat of this sense. 
There is abundant evidence of the existence of a sense of smell. 
In fact this sense is particularly well developed in many insects, and 
serves to guide them to their food, to lead the females to the proper 
plants on which to deposit their eggs, and often to bring the male to 
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