202 ON INSTINCT IN MAN AND ANIMALS. 
animals not very far removed from ourselves, before 
we pronounce positively as to the nature of the mental 
operations in creatures so radically different from us 
as insects. We have not yet even been able to ascer- 
tain what are the senses they possess, or what relation 
their powers of seeing, hearing, and feeling have to 
ours. Their sight may far exceed ours both in delieacy 
and in range, and may possibly give them knowledge 
of the internal constitution of bodies analogous to that 
which we obtain by the spectroscope; and that their 
visual organs do possess some powers which ours do 
not, is indicated by the extraordinary crystalline rods 
radiating from the optic ganglion to the facets of the 
compound eye, which rods vary in form and thickness 
in different parts of their length, and possess distinc- 
tive characters in each group of insects. This complex 
apparatus, so different from anything in the eyes of 
vertebrates, may subserve some function quite incon- 
ceivable by us, as well as that which we know as 
vision. There is reason to believe that insects appre- 
ciate sounds of extreme delicacy, and it is supposed 
that certain minute organs, plentifully supplied with 
nerves, and situated in the subcostal vein of the wing 
in most insects, ‘are the organs of hearing. But be- 
sides these, the Orthoptera (such as grasshoppers, 
&c.) have what are supposed to be ears on their fore 
legs, and Mr. Lowne believes that the little stalked 
balls, which are the sole remnants of the hind wings 
in flies, are also organs of hearing or of some ana- 
logous sense. In flies, too, the third joint of. the 
