PHYSICAL ANTECEDENTS OF SCIENCE 131

Still more incredible is it, however, that a grub should

foresee the shape of the body it is destined later to ac-

quire, especially when this shape is widely different in

the two sexes. Yet the grub of the female stag-beetle,

when she digs the hole wherein she will undergo her meta-

morphosis, digs it no bigger than her own body ; whereas

the grub of the male stag-beetle makes a hole twice as

large as his own body, in order to leave room for the

enormous jaws (the so-called "horns") which he will have

to grow.

One more example of that function of the nervous system

which results in instinct must here suffice.

There is a kind of beetle, called "sitaris," which is para-

sitic on certain bees, while its relation to those insects is

very different during the very different stages of existence

which make up its life-history.

It is hatched from eggs which the mother sitaris lays

in passages in the bee's nest. Instead of being in the form

of a grub (as is the case with beetles generally), it comes

forth from the egg as an active, six-legged little insect with

eyes and two long " feelers," or antennae. In the spring, as

the male bees (drones) pass out for their nuptial flight

with the queen, the sitaris attaches itself to one of them,

and as soon as the opportunity offers, passes from it to

the body of the queen bee. When, afterwards, the queen bee

lays her egg in the hive, the sitaris springs upon it, and

is unsuspectingly enclosed in a cell with the honey destined

to nourish the bee-grub when the queen's egg is hatched.

Thus left alone with the egg, the sitaris devours it, and then

undergoes a transformation in the empty egg-shell. Having

been active in the earliest stage of its life it assumes the

helpless form of a fleshy grub, which floats on the honey and

gradually consumes it. Afterwards it transforms itself once

more, and regaining six legs, emerges as a peaceful beetle,

Still more incredible is it, however, that a grub should

foresee the shape of the body it is destined later to ac-

quire, especially when this shape is widely different in

the two sexes. Yet the grub of the female stag-beetle,

when she digs the hole wherein she will undergo her meta-

morphosis, digs it no bigger than her own body ; whereas

the grub of the male stag-beetle makes a hole twice as

large as his own body, in order to leave room for the

enormous jaws (the so-called "horns") which he will have

to grow.

One more example of that function of the nervous system

which results in instinct must here suffice.

There is a kind of beetle, called "sitaris," which is para-

sitic on certain bees, while its relation to those insects is

very different during the very different stages of existence

which make up its life-history.

It is hatched from eggs which the mother sitaris lays

in passages in the bee's nest. Instead of being in the form

of a grub (as is the case with beetles generally), it comes

forth from the egg as an active, six-legged little insect with

eyes and two long " feelers," or antennae. In the spring, as

the male bees (drones) pass out for their nuptial flight

with the queen, the sitaris attaches itself to one of them,

and as soon as the opportunity offers, passes from it to

the body of the queen bee. When, afterwards, the queen bee

lays her egg in the hive, the sitaris springs upon it, and

is unsuspectingly enclosed in a cell with the honey destined

to nourish the bee-grub when the queen's egg is hatched.

Thus left alone with the egg, the sitaris devours it, and then

undergoes a transformation in the empty egg-shell. Having

been active in the earliest stage of its life it assumes the

helpless form of a fleshy grub, which floats on the honey and

gradually consumes it. Afterwards it transforms itself once

more, and regaining six legs, emerges as a peaceful beetle,