ed groups of
animals.

V.

ON INSTINCT IN MAN AND ANIMALS.

The most perfect and most striking examples of what is termed instinct,
those in which reason or observation appear to have the least influence,
and which seem to imply the possession of faculties farthest removed
from our own, are to be found among insects. The marvellous constructive
powers of bees and wasps, the social economy of ants, the careful
provision for the safety of a progeny they are never to see manifested
by many beetles and flies, and the curious preparations for the pupa
state by the larvae of butterflies and moths, are typical examples of
this faculty, and are supposed to be conclusive as to the existence of
some power or intelligence, very different from that which we derive
from our senses or from our reason.

_How Instinct may be best Studied._

Whatever we may define instinct to be, it is evidently some form of
mental manifestation, and as we can only judge of mind by the analogy of
our own mental functions and by observation of the results of mental
action in other men and in animals, it is incumbent on us, first, to
study and endeavour to comprehend the minds of infants, of savage men,
and of 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 ascertain 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 delicacy 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 distinctive characters in each group of
insects. This complex apparatus, so different from anything in the eyes
of vertebrates, may subserve some function quite inconceivable by us, as
well as that which we know as vision. There is reason to believe that
insects appreciate 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