s rearing
her young, it would appear that the male uses his brilliancy to lure
the observing enemy away from the nest containing his wife and
children.

Another illustration of the remarkable superiority of the male over
the female, in many parts of the bird world, is seen in the case of
the common barnyard fowl. The rooster is so much more gorgeous than
the hen that anyone reasonably acquainted with these birds cannot have
failed to notice the fact. In some of our modern varieties we have by
breeding colored them nearly alike. The original chicken is colored
much like the common Leghorns. Shades of red and yellow decorate his
neck and back, while the flight feathers of his wings and of his tail
and the sickle feathers which ornament the rear of his back and hang
over his tail are lustrous dark green. The hen meanwhile is very much
less brilliant in her contrasts. I shall speak more fully of this in
discussing polygamy.

The attraction of beauty is not the only lure by which a creature may
win its mate. Sound may captivate as effectively as beauty. This is
true of insects as well as of birds. Certain insects at least advise
their mates of their presence by means of a sound which they emit.
This is particularly noticeable among the group of straight-winged
insects to which the grasshopper, katydid and cricket belong. The
grasshopper has a ridge on the angle of his wing and a roughness on
the side of his leg. When these two are rubbed together the result is
sometimes a fiddling, sometimes a snapping or cracking sound,
differing in different grasshoppers. I doubt not these sounds are
pleasing to the female of the species, for they are always made by the
male. The katydid, instead of fiddling in this way, has a sort of drum
on the angle of his one wing, which he can rub over a tooth in the
corresponding angle of his other wing, thus producing the familiar
"katydid" sound. I have never succeeded in making a dead grasshopper
fiddle, but I have long known how to make a dead katydid say "ka."
Quite recently I have added to my accomplishment in this respect and
can make it say "katy." The "did" part of the song still lies beyond
my power. The crickets produce their sharp notes in much the same
fashion as the katydids.

One observer of the chirping of the cricket says that the pitch of the
song varies with the temperature. He has even worked out a formula by
which one can tell the pitch of the chirp, if he knows the
temperat